Aug
03
2006

The chicken and the egg

I've noticed a lot of dead fledglings and raided nests lately. Sometimes, mixed in with all the broken eggshells, I find an unhatched baby bird. And that got me wondering: are grocery store eggs fertilized? How come you never come across one with an embryo or a little chicken inside? If they're not, why does a chicken spend the energy required to produce unfertilized eggs?

Egg (and chicken): (Photo by Peter Cooper)
Egg (and chicken): (Photo by Peter Cooper)

When you google "are chicken eggs fertilized?" you get a lot of responses. Guess lots of other people had the same question.

The answer is that chickens will lay eggs even when they've had no contact with a rooster. According to the "Ask a Scientist" feature of the Howard Hughes Medical Institute,

"If an egg has been fertilized, then the embryo inside has already divided several times but remains a group of unspecialized cells [at the time the egg is laid]. When the egg is incubated at about 37 to 38 °C, the embryonic cells differentiate to form a chick, which will hatch after 21 days. If the egg has not been fertilized, then the oocyte [or egg cell] within will never grow or divide, and the egg will never hatch. The eggs you buy at the supermarket are eggs that have never been fertilized.

Domestic chickens lay one egg every 26 to 28 hours (about one egg a day) for a period of 4 to 6 days. In between periods of egg laying, the hen rests. Wild birds may rest for months before laying more eggs, but domestic hens, specially bred for abundant egg production, may rest for as little as 1 day between egg-laying periods."

In commercial egg operations, hens are kept away from roosters, and the eggs are collected as they're laid. Chickens raised to produce eggs only need to mate to replace hens that get too old to lay eggs.

Sometimes you come across a grocery store egg that contains a blood spot. I was told, as a child, that a blood spot indicated a fertilized egg. But that's not so, according to the American Egg Board. Instead,

" Contrary to popular opinion, these tiny [blood] spots do not indicate a fertilized egg. Rather, they are caused by the rupture of a blood vessel on the yolk surface during formation of the egg or by a similar accident in the wall of the oviduct. Less than 1% of all eggs produced have blood spots.

Mass candling methods reveal most eggs with blood spots and those eggs are removed but, even with electronic spotters, it is impossible to catch all of them. As an egg ages, the yolk takes up water from the albumen to dilute the blood spot so, in actuality, a blood spot indicates that the egg is fresh. Both chemically and nutritionally, these eggs are fit to eat. The spot can be removed with the tip of a knife, if you wish."

What about those weird white stringy bits you see when you crack an egg? The American Egg Board says they're called chalazae:

"[Chalazae (singular=chalaza) are] ropey strands of egg white which anchor the yolk in place in the center of the thick white. They are neither imperfections nor beginning embryos.

The more prominent the chalazae, the fresher the egg. Chalazae do not interfere with the cooking or beating of the white and need not be removed, although some cooks like to strain them from stirred custard."

Here's a neat site about the structure of a chicken egg.

And another one about how a hen lays an egg.

Egg trivia

And a bunch of other resources about chickens and eggs.





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Your Comments, Thoughts, Questions, Ideas

Jeff's picture
Jeff says:

Heh, thanks for this. My 2 year old was just asking me today if his scrambled eggs had birds inside them, and while I knew the answer was no, I didn't actually know why until I googled and found this post.

posted on Sat, 08/05/2006 - 1:52pm
Anonymous's picture
Anonymous says:

Smart kid to be asking such intrinsic questions that early :D

posted on Sun, 07/05/2009 - 11:30am
Anonymous's picture
Anonymous says:

Sometimes hens can produce chicks from unfertilised eggs, 100% of the mothers genes. Well documented

posted on Sat, 09/04/2010 - 7:02pm
Jacquie Jacob's picture

I've not heard of such a thing - biologically it would be impossible since the ova in the ovary of a female chicken contain only 1/2 of the genes needed for a new individual. Would love to see your documentation.

posted on Wed, 09/08/2010 - 6:16am
Jacquie Jacob's picture

Having made my previous statement I found reports that they have - http://www.thepoultrysite.com/articles/837/parthenogenesis-embryonic-dev... - so I retract me previous assertions. Thanks for pointing it out to me.

Parthenogenesis refers to the ability of unfertilized chicken and turkey eggs to develop embryos. In 1953, Olsen and Marsden, two scientists at the Agricultural Research Center in Beltsville, Maryland, accidentally discovered parthenogenesis in turkeys. They found that 14% of the infertile eggs laid by Belts-ville Small White (BSW) turkeys developed partheno-genetically. However, almost all parthenogenic development in unfertilized turkey and chicken eggs is very unorganized and closely resembles normal embryonic mortality during the first three days of incubation in the fertilized egg.
Parthenogenetic embryos have a time lag in development, usually requiring two days longer incubation time than do normal embryos from fertile eggs. Additionally, the incidence of parthenogenesis is greater in double yolk eggs as compared to single yolk eggs. Double yolk eggs remain in the uterus longer than single yolk eggs so that adequate shell can be created on such a large egg. Perhaps this ex-tra time in the uterus allows for a greater length of embryonic exposure to body temperature and more time for the delayed parthenogen to develop inside the hen’s body.

posted on Wed, 09/08/2010 - 6:26am
Jacquie Jacob's picture

Parthogenesis is an interesting topic - thanks for bringing it up. It is a rare occurence and appears to be a genetic trait. Lines of turkeys have been selected for a higher than normal incidence of parthogenesis. All the offpsring are male indicating it is the set of genes with the Z chromosome that is duplicating itself (female birds are ZW while males are ZZ, so unlike mammals, the female bird genetically determines the sex of the offspring).

posted on Wed, 09/08/2010 - 6:34am
Shana's picture
Shana says:

That's so interesting--I wonder if this would be an example of convergent evolution? It seems unlikely that the birds would have kept parthenogenesis from bacteria, especially when I think that parthenogenesis in bacteria produces clones of the parent...but then again I am not a biologist.

posted on Wed, 09/08/2010 - 10:55am
khaliphile's picture
khaliphile says:

what is the purpose of laying eggs in clutches? what is happening when eggs are laid together?

posted on Sat, 03/03/2012 - 5:45am
Jacquie Jacob's picture

Birds have only one oviduct and it takes 24-26 hours to 'create' an egg and they can't create an egg till the one they have been working on is laid. The hens are stimulated by light to lay. With more than 24 hours to produce an egg they starting laying later and later each day. They reach a point where they are laying too late in the afternoon to be stimulated by the light to ovulate (start of creating another egg) so they miss a day or two. The number of eggs laid day-after-day without a break are referred to as a clutch.

posted on Mon, 04/02/2012 - 5:57am
Anonymous's picture
Anonymous says:

Hi, it's called parthenogenesis, greek virgin birth, it can happen in birds, but more commonly in reptiles ect.

posted on Fri, 02/25/2011 - 11:04pm
Happychickens123 in Fallbrook's picture

I've been raising chickens for a while now and have many eggs.. my own kids will not eat the eggs cuz they said the stringy stuff was the "cord" of a baby chick, I knew that wasn't true but they wouldn't listen to me - so thanks for the explanation - I should have them research it a long time ago - they missed out on a lot of fresh eggs, their loss

posted on Thu, 08/04/2011 - 11:10pm
Anonymous's picture
Anonymous says:

Hi I have just had a friend give us eggs from their chickens which i think are fertile. They had collected the day before and so they had spent a day in the fridge. We have now placed them under our nexting chicken, is their a chance of chicken in 21 one days

posted on Thu, 05/26/2011 - 8:10pm
Jacquie Jacob's picture

One day in the fridge should not be a problem. If the eggs are fertile and the incubator is running properly, you should get chicks hatching out in 21 days.

posted on Fri, 05/27/2011 - 10:58am
Jenny Dorsainvil's picture
Jenny Dorsainvil says:

hi um i just brought eggs yesterday and they spent one day in the fridge and now im getting ready to put it in an incubator but can they hatch in 21 days because of that?

posted on Mon, 07/04/2011 - 1:49pm
Jacquie Jacob's picture

I day in the fridge shouldn't be a problem. As long as they are fertile, and the right incubation conditions are used, they should hatch.

posted on Tue, 07/05/2011 - 11:23am
Anonymous's picture
Anonymous says:

i liv in dubai. suddenly wild pegions started to lay egg on our balcony. i very exicted now . i wanted to know wether frozen chicken eggs can be hatched.

posted on Wed, 08/17/2011 - 4:46am
Jacquie Jacob's picture

NO frozen chicken eggs cannot be hatched. The freezing will kill any embryos that might have been there.

posted on Mon, 08/22/2011 - 7:59am
Anonymous's picture
Anonymous says:

Hello, my chicken was laying eggs for a few weeks but all of a sudden she stopped. i wanted to know what it was that was making her not able to lay eggs anymore. thanks a bunch

posted on Wed, 08/23/2006 - 5:14pm
Liza's picture
Liza says:

I found this on the Howard Hughes Medical Institute Ask a Scientist website:

"Domestic chickens lay one egg every 26 to 28 hours (about one egg a day) for a period of 4 to 6 days. In between periods of egg laying, the hen rests. Wild birds may rest for months before laying more eggs, but domestic hens, specially bred for abundant egg production, may rest for as little as 1 day between egg-laying periods."

So maybe your hen is resting? Egg laying is also related to hours of daylight. Once a hen no longer gets about 14 hours of light a day, she tends to quit laying.

Without more information, it's hard to say. But this page from the Virginia Cooperative Extension might help. Or this one, PoultryHelp.com.

posted on Mon, 09/11/2006 - 10:14am
Alexis's picture
Alexis says:

Chickens will also stop laying if they're "clucky". Which basically means that they think that their eggs are fertilized and therefore sit on them for ages. I've heard of many ways of curing a chicken of "clucky-ness", things like: dipping them in a barrel of water for a sec (personally I've never tried it, but if you decide to, then do it on a warm summer day so she can dry out and not get a cold or die of a flu), or one that my mum used to do to our chookies was but them in a dark small, dark box for 24 hrs it's not mean as they really don't mind but they just loose sense of time and think that their babies have already hatched or something. But they'll get over it eventually, so if you don't want to do anything drastic or can't stand to lock your beloved pet in a box overnight the don't fret to much.

I remember quite vividly my uncle told me when I was about six that the best way to cure a "clucky" chicken was to put it in the oven and then on the dinner table. It took me a second to understand and when I did I kicked him in the shin quite hard and told him he was a big meanie and I wouldn't let him near my speckles (pronounced more like 'thbekels') which was the name of my chicken.
I was mad and I managed to ignore him for about an hour and a half before he bribed my adoration with a sweet.

Anyway, that's all.

posted on Thu, 05/03/2007 - 9:20pm
Anonymous's picture
Anonymous says:

its called a broody hen not "clucky"

its broodiness not "clucky-ness"

and 4 more info about makeing and breaking broodiness pleast read the following

"Storey's Guide to Raising Chickens

my email is turtmaster@yahoo.com

posted on Wed, 06/11/2008 - 12:00am
L B M's picture
L B M says:

I was also told this was called being clucky. When my hens to that they have to spend a couple of days in the "butt box". I was told that the hen needs to let her "bottom side" get cold. This stops the feeling of incubating her eggs. I have a dog crate that has a wire bottom. I raise the crate up an inch or two so when she sits down her bottom is off the ground. She has food and water in there and it's outside the coop so she gets sunshine too. Two to 3 days in the butt box and she's back to her old self.

posted on Wed, 11/10/2010 - 1:37pm
fatima's picture
fatima says:

oh my god i dont know how to really thanks you this really helped me with my science project i dont know what to say anymore but thank you very much it quiet interesting and by the way i am 13 yr old and i am in 8 grade

posted on Thu, 10/04/2007 - 11:26pm
Anonymous's picture
Anonymous says:

Chickens also stop laying when they moult. In the fall the hens loose their summer feathers and get new winter feathers. This is a stressful time for their body and they stop laying. Look closly at your chickens. Are they getting brighter and look cleaner. Once they stop moulting they will go back to laying. Also what the person said about the time frame of laying is correct. They can go for days and lay and then they rest for a day or so.

posted on Tue, 10/10/2006 - 11:01pm
Eser's picture
Eser says:

Your chicken may be sick !!!!!

posted on Sat, 08/11/2007 - 4:49pm
barb's picture
barb says:

Probably stress or change in diet or age. As they age or in colder weather they lay less. Make sure she has a varied high protein diet, fresh water, and exercise. Does she behave normally or are they any stressers liek dogs?

posted on Wed, 03/04/2009 - 12:37pm
Anonymous's picture
Anonymous says:

if she lost her feathers and grew new ones back she was molting tipically hens stop laying while molting

posted on Mon, 11/30/2009 - 10:32pm
Dallas's picture
Dallas says:

Hello,
In case you didnt find this out already it is because chickens stop all of a sudden when they feel that is enough for now and will wait until the eggs have hatched and are old enough to go on there own. Then the hen will lay eggs again. They wont lay eggs and then lay eggs a couple of days later because they dont want to have eggs hatching all different times.

Chickens are very smart.

posted on Sun, 12/27/2009 - 4:04am
Jacquie Jacob's picture

Chickens reproductive patterns are related to the number of hours of light each day. They are stimulated to come into production when days are increasing in the number of hours of light. Days with decreasing hours of light typically cause chickens to go out of production. Controlling the number of hours of light per day (plus some genetic and management improvements) allow for commercial chickens to lay year round.

Avian embryos have a property known as 'physiological zero' in which an embryo will go into stasis and stop development until incubated (naturally or artificially). It takes 24-26 hours for a hen to put together an egg from ovulation till it is laid (known as oviposition) and the female ova gets fertilized at the begining of this trip through the oviduct. As a result, the embryo is 24 hours old when laid. No further embryo development will occur until the egg is incubated. This allows a hen to lay several eggs but have them all hatch at the same time.

posted on Thu, 12/31/2009 - 2:37am
Deborah's picture
Deborah says:

I have 1 rooster and 15 hens, they are of different breeds and I don't raise them, just gather eggs. I do have 1 polish female of the same color as my rooster. If I decide to separate her and allow her to hatch eggs just because she is loose with him will all her eggs be fertile? How will I know if her eggs are fertile, I guess is my question?

posted on Sat, 03/13/2010 - 1:30pm
Jacquie Jacob's picture

There is no guarantee that ALL eggs will be fertile. You should have a high percentage of them. 1 rooster for 15 hens is stretching him a bit thin though. You can't tell if fresh eggs are fertile or not without breaking them open. The only way is to incubate them and candle after a week and see if there is an embryo inside or not.
She has to go broody to sit on the eggs - and won't do it just because the timing is good for you.

posted on Mon, 03/15/2010 - 12:32pm
Pete's picture
Pete says:

I have 15 hens that have been laying consistently for 6 months. I also have 3 roosters that i removed from the hen yard this spring because they became just too aggressive.

I have decided that I want to incubate my own eggs for additional layers to add to the flock. My question is, once I put a rooster back into the hen yard how long will it take for fertilized eggs to show up. Once I know they are fertile i can begin collecting them for incubation.

posted on Sat, 04/10/2010 - 10:29pm
Jacquie Jacob's picture

I assume you are the same person who posted the question at the end of page 3 of the blog. My answer there was:
"Assuming the hens are laying [which you verfied in this posting], and taking into account that it takes 24-26 hours to create an egg from ovulation (release of yolk from the ovary) to oviposition (actually laying the egg), the eggs from the first few days shouldn't be used.
Assuming you have the correct number of males to females [the three roosters you have should be sufficient for 15 hens], they should start laying fertilized eggs after a week or so. To increase the percent fertilzed, I would wait at least two weeks."

posted on Tue, 04/13/2010 - 6:30am
Anonymous's picture
Anonymous says:

How long does a fertilized egg stay good before the hen needs to sit on it?? I have planted some fertilized eggs in a nesting box and after 8 days I finally have a hen that has gone broody. But are the eggs bad at this point??

posted on Fri, 04/16/2010 - 8:33am
Jacquie Jacob's picture

Q1 - How long does a fertilized egg stay good before the hen needs to sit on it?
A1 - You can't make a hen broody (she has to have the right hormonal changes before she will go broody) so putting eggs under her before she goes broody is never a good idea. If you want to do something to try and trigger broodiness I would suggest trying golf balls or some other object rather than eggs. If they get broken you can start an egg eating problem.

Q2 - Are the eggs bad after 8 days in the nest?
A - Depends on the ambient temperature. Hatching eggs should be stored at 50-55F if saved for 8 days. At warmer temperatures (but not at incubating temperature) you have an increased likelihood of getting dead or deformed chicks.

Nothing is certain with incubation, just probabilities. I would suggest candling the eggs to see if there is any embryo development (with embryos still living). If the eggs are clear or have blood rings I would throw them out.

If it was me and I had the eggs, I would switch them for fresher ones.

posted on Mon, 04/19/2010 - 7:46am
Sarah-Beth : the farm gal's picture
Sarah-Beth : the farm gal says:

okay first i raise chickens and sell eggs too

but the way i've learned is that you chickens
* may be old!
* it's cold or the sun is not hitting them enough get lights installed the coop, and if serous get lights that turn on at different times
* okay ask your local feed store for shells for chickens or the small clams, to help the chicks digest or bake your egg shells BUT WATCH THEM BAKE THEY WILL BURN FAST!!!!
*idk and more questions " WWW.lsu-girl@hotmmail.com" bue glade to answer

posted on Tue, 01/19/2010 - 7:18pm
Anonymous's picture
Anonymous says:

Are unfertilized eggs that have been stored in a refrigerator considered dead or alive?

posted on Sun, 09/10/2006 - 4:17pm
Liza's picture
Liza says:

I'm not quite sure that I understand your question.

Since the eggs are unfertilized, there are no embryos, alive or dead.

If you're asking if the cold renders the oocyte itself (i.e. the genetic package contributed by the hen, not the rooster, and not the hard-shelled object familiarly called an egg) inviable, that's an interesting question. But it's also a moot point. Once an egg is laid, it can no longer be fertilized.

posted on Mon, 09/11/2006 - 9:43am
Liza's picture
Liza says:

I found the following exchange on the Roger Tory Peterson Institute of Natural History's Electronic Naturalist website, where naturalist John Weissinger answered people's egg questions:

"Q: Can you hatch a chicken from an egg in your refrigerator?

A: Yes you can but only if your egg is fertile to begin with. Most of the eggs sold in stores come from large chicken farms where the hens are maintained totally separate from males. No males, no fertile eggs! If you get eggs from chickens that are free range, then there is a good, or at least better, chance that you'll have fertile eggs. An egg can be quite cool BEFORE incubation starts but once it has started, you'd need to maintain a reasonably constant warm temperature. Hope this helps."

posted on Mon, 09/11/2006 - 9:51am
Anonymous's picture
Anonymous says:

My daughter has a pet chicken (Sally). Sally is her best friend. The Sally waits for my daughter to get off the bus, and comes and knocks on the door so that she can go out to play. Tonight, I went to put the chickens in for the night and Sally was not around. We have three eggs from the last three days (they are in the ref.) and I was wondering if they would hatch? Please let me know.
Thank you, Lori.

posted on Wed, 04/11/2007 - 10:27pm
Anonymous's picture
Anonymous says:

If ref. is short for refrigerator and they've been in there for three days the chances of them hatching is 1 to 1,000 so don't even try to do anything about it

posted on Sat, 05/12/2007 - 8:35pm
Anonymous's picture
Anonymous says:

An egg cannot get below 40 degrees or it is no longer viable. You cannot put a fertilized egg in the refrigerator and expect it to hatch when you put it in the incubator. People need to do research before answering somebodies question.

posted on Fri, 02/15/2008 - 1:05pm
Liza's picture
Liza says:

I cited my source--a reputable expert. And my answer was reviewed, after posting, by local poultry expert Jacquie Jacob. So I stand by it.

But you're right: people should research the answers to questions before posting them. An incorrect answer isn't helpful to anyone.

posted on Fri, 02/15/2008 - 2:44pm
Anonymous's picture
Anonymous says:

eggs that have been in the fridge and that are fertile will hatch, I was given some eggs that had spent a few days only in the fridge and I hatched some under a hen and some in the incubator, this was chicken and duck eggs, it is not a great pratice but it can be done.

posted on Sat, 09/27/2008 - 7:31am
I have chickens 2's picture
I have chickens 2 says:

I agree with Anonymous................you really need to do some research before answering anyone's questions, they really want the truth and really want to know what to do, how to do it and all the how to's. It seems really like common sense if you put a bunch of eggs in the icebox and they get real cold...do you really think you can take them out and heat them up and hatch a egg into a chicken? Think about it...the incubation process...they have to be at a certain temperature for 21 days talking about chickens, I just hatched over 100 guineas from eggs. Eggs left outside in cold temperatures can freeze and they are no longer good. I agree with Anonymous, ask them your questions.

posted on Fri, 02/29/2008 - 8:17am
Liza's picture
Liza says:

OK, read the original question: The poster wanted to know if it was possible that eggs kept in the refrigerator for three days, that had never been incubated, could still hatch. And my answer was, it's possible. If the eggs aren't frozen, and development hadn't begun (i.e. they weren't being incubated), it IS possible that the eggs could hatch.

It's not a recommended practice for people who are trying to raise chickens. But that's not what the questioner wanted to know. She just wanted to know if it was possible. And it is.

posted on Fri, 02/29/2008 - 10:56am
Kathleen P.'s picture
Kathleen P. says:

It is possible for a fertilized egg that has been in the refrigerator to hatch.We hatched our pet turkey Charlie from a group of four eggs that were in the refrigerator for about 24hrs.Only one of the eggs hatched so the chances are slim but possible!

posted on Wed, 03/12/2008 - 10:40am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Most refrigerators store feed at 45F, which is too cool for successful hatching of fertile eggs - though, as you noted, it is possible (your odds just go down). Hatching eggs are best stored at 55F. Then they can be stored for a week or more with a relative high success of hatch.
So to answer the original question - it is possible for the eggs to hatch, but the probabilities go down with a lower temperature and with time in storage. Chicks are extremely resilient and anything is possible.

posted on Thu, 03/13/2008 - 7:56am
Ovapository's picture
Ovapository says:

Dear Dr.Jacquie,
I love your advice. I so agree with you that with chicks and chickens anything is possible. I had two small Arrucana hens, who stole eggs from my large Rhode Island Red hens. I knew they had gone broody together, but every morning they would both be sittling on a larger and larger pile of eggs. I finally started going out very early with my german shepherd dog(who thought he was their mother) to observe how this could be happening. My chicken house was a very large old rabbit hutch my husband had built for me many years before. I had him remove the partions between each hutch and I laid down removable mats for easy cleaning and always kept deep saw dust on the floor. The hens all made their nests in the sawdusts so I didn't need boxes. Well, as I watched each morning, those two little dickens would make their way to the sitting Rhode Island Reds and literally bully them off their nests. Then those two little stinkers would roll how ever many eggs they found to their two nests and sit there, innocently, side by side. I told the folks down at the feed store about it. There were quite alot of people there at the time and every one had an opinion. But they all concurred that the amount of eggs they were trying to sit and two hens doing it together (they said they would begin to fight over the eggs) they said nothing would hatch and I should throw all the eggs away and separate the two little hens. I'm a school teacher and have all summer off, I love science and animals. Those two little girls seems to be friends and very serious in their efforts and I was very curious to see what they would do. So I got a small portable dog house, and made a small portable run that was sheltered well and my husband helped me move the two girls and their eggs very carefully. We ended up finding and returning 39 eggs under the two of them. I recorded everything in a diary, it was hilarious and heartwarming and the picture of feminine nobility the way those two little birds dedicated themselves to those eggs. The first peeping I heard I brought the baby in the house as it had fallen off the mountain of eggs and couldn't get back under the mommies. We named her Ridiculous and my son tamed and taught her from the minute I brought her inside. We ended up having so many chicks hatch at so many stages, I had boxes with heat lamps set up all over my family room. We ended up with 6 boxes and the final tally was 27 live chicks out of 39 eggs. In short, I am so agreeing with you. With chickens anything is possible!

posted on Mon, 07/04/2011 - 1:21pm
chicky's picture
chicky says:

my friends egg dropped in class today it was refrigerated and it had a head forming!

posted on Wed, 05/07/2008 - 10:26pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

I am curious as to what you saw that you indicated that a head was forming. Also, were you indicating that the egg was refrigerated before incubating - how long had it been stored in the refrigerator, what temperature was the refrigerator (the ideal temperature for storing hatching eggs is 55F), and how long had it been in the incubator before it was dropped?

posted on Thu, 05/08/2008 - 2:22pm
Anonymous's picture
Anonymous says:

I was given 6 eggs from a fridge, 5 were fertile and 4 hatched out and were very health chicks, my sister also did the same and was also successful, so it can be done.

posted on Thu, 05/27/2010 - 4:33am
Jacquie Jacob's picture

In poultry production we talk percentages or likelihood of something happen. It is never impossible, just less likely as storage time increases.
5 out of 6 is pretty good.How long were they in the fridge for, and at what temperature? These are usually the determining factors.

posted on Fri, 05/28/2010 - 6:16am
Skye's picture
Skye says:

Okay, my classmates and I are arguing back and forth about this one...Can you see the "sperm" or "sperm sack" on a fertilized chicken egg. I've read that the white, stringy thing, the Chalazae, is the "sperm sack", now, I read here that it anchors the yolk. So can you clarify, can you tell by looking at a cracked, raw egg; has it been fertilized. p.s I do buy farm fresh eggs where roosters reside w/ the hens.

posted on Mon, 09/25/2006 - 10:03am
Liza's picture
Liza says:

According to the Ohio State University extension service, the yolk of a fertilized egg has something called a "blastoderm," while an unfertilized egg has a "blastodisc." (You can see a picture here.)

If you don't crack the egg open, but instead observe it by candling, these pictures will help you distinguish between fertile and infertile eggs. Or these.

I'm a city girl, not a chicken expert. But I can tell you what *I* think, and then quote an expert!

My guess would be that, no, you can't see sperm in a fertilized chicken egg. Why? Two reasons. Male chickens do produce packets of sperm, but they go to fertilize many eggs, not just one. (I read a lot about chicken sex--more than I ever wanted to know!--to answer questions related to this post...) Second, chicken eggs (oocytes) are fertilized before the eggs (white, hard shells, crack 'em and cook 'em to eat 'em with bacon) are laid. By the time the chicken lays a fertile egg, the sperm and oocyte have united and the embryo inside the egg has even already divided a bunch of times. So you wouldn't be seeing sperm in a cracked egg.

Dennis Chang, of Harvard University, had this to say:

"Birds, like mammals, use internal fertilization. Many species of birds lack a penis; instead, the male just has a genital opening (cloaca), which must be positioned against the female's genital opening (also called a cloaca) for sperm transfer. Male chickens, however, do have a small penis to facilitate mating. In any case, after copulation, which only lasts a few seconds, the sperm quickly swim up the oviduct toward the ovary. The sperm can stay alive in the oviduct for several weeks, ready to fertilize the next egg cell (oocyte) that appears.

Oocytes are produced in the ovary, packaged with yolk within a thin protein membrane, and released one at a time into the funnel-like infundibulum of the oviduct. The oviduct is a tubular passageway leading from the ovary to the outside world. It is also an assembly line in which the various layers of the egg are constructed. After an oocyte-yolk package is released into the infundibulum, it lingers there for about 20 minutes. If sperm are present, then the oocyte is fertilized and becomes an embryo. But if no sperm are around (that is, if the hen has not mated), then the egg still proceeds down the assembly line of the oviduct. In this assembly line, albumen (egg white) is added around the yolk, shell membranes are added, and the shell itself is constructed. Finally, the complete egg is pushed through the vagina and out the cloaca.

If the egg has been fertilized, then the embryo inside has already divided several times but remains a group of unspecialized cells. When the egg is incubated at about 37 to 38 °C, the embryonic cells differentiate to form a chick, which will hatch after 21 days. If the egg has not been fertilized, then the oocyte within will never grow or divide, and the egg will never hatch."

Does that answer your question?

posted on Mon, 09/25/2006 - 12:40pm
Tom's picture
Tom says:

Can you clarify the fertilized egg issue.....if you have a rooster in the hen house, how can you tell which eggs are fertilized and which are not?

If the egg takes 21 days to hatch, an unfertilized egg will be long past the edible stage so you've wasted an egg. But if you collect the eggs daily, you risk destroying a fertilized egg. If you candle the egg after 10 days, you again have wasted an edible egg.

Do you see my dilemma? How do you tell the egg is fertilized, right after it's layed, so you don't waste either an edible egg or a fertilized egg?

posted on Wed, 12/27/2006 - 1:39pm
Liza's picture
Liza says:

Well, I don't keep chickens, but everything I've read suggests that if you keep hens and a rooster together, you should assume that eggs are fertile unless it becomes obvious that they're not.

I don't think there's any reason you shouldn't eat a freshly-laid, fertile egg if that's why you're keeping the chickens. After all, if you eat the adults... Also, a fertilized egg, once laid, is in a state of suspended animation until it's incubated. If you collect the egg right away and refrigerate it, the embryo will never develop, and I'll bet you'd never notice the difference between that egg and an unfertilized one.

If you want to eat the eggs but don't want them fertilized, keep the hens and the rooster separate. It's the only way to be sure.

posted on Wed, 12/27/2006 - 5:06pm
Tom's picture
Tom says:

My question is, how do you avoid the waste. I'm not worried about eating fertilized eggs. There must be a more accurate way of telling which eggs are fertilized and which eggs are not.

Let's say you are raising chickens to sell the eggs, but you also want to steadily replace older hens so your egg supply stays constant. If you isolate some chickens with a rooster so that they will reproduce, how do you know which eggs from that bunch are fertilized/unfertilized?

You would want to incubate the fertilized eggs and still sell the unfertilized eggs. But by not being able to tell and only guessing, you would end up incubating eggs that aren't fertilized, thereby losing some of your saleable eggs. And, if you guessed wrong that an egg wasn't fertilized and collected it for sale, you thereby destroy a potential chick that could have strengthened your chicken supply.

There has to be some method for identifying which is which.

posted on Thu, 12/28/2006 - 10:09am
Anonymous's picture
Anonymous says:

If you candle them (Hold the egg up to the light) you can see if it's been fertilized. Thee will be a mass there.

posted on Thu, 12/28/2006 - 1:30pm
Anonymous's picture
Anonymous says:

Thank you for telling me how to tell if the egg is fertilized without having to break it open.

posted on Mon, 03/19/2007 - 7:24pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

You can't actually tell whether or not an egg is fertile or infertile by candling - unless the egg has been incubated for 2-3 days so that the embryo is large enough to see.

Table eggs are candled to verify the interior quality, including the presence of blood or meat spots (which are not embryos).

You can only tell whether or not an egg is fertile or infertile by breaking it open. An infertile egg will have a small white spot on the yolk. This is called the blastodisc and represents the female genetic material. If the egg is fertile the white spot will appear more like a donot (white ring with clear area in the middle). This is the blastoderm (or germinal disc) and is the developing embryo. It takes the hen 24-26 hours to assemble an egg, and the egg is fertilized before the process begins. Thus the embryo is 24-26 hours old when it is laid.

You can see the differences between infertile and fertile eggs online.

See the parts of the egg, including the germinal disc.

Once a fertile eggs has been incubated 2-3 days post-lay the embryo is large enough to see. Online, you can see some candling photos.

posted on Tue, 04/10/2007 - 12:27pm
Ed Anonymous's picture
Ed Anonymous says:

How do you know when a chicken is born if it is male or female. How long can you keep eggs at room temp or in the nesting box if the hen won't brood before incubating them? What's the best way to incubate without a big expense? If you touch a chickens eggs will it sit on it to brood? I want from real knowledge. Not wise tales. Thanks!

posted on Tue, 09/28/2010 - 9:55am
Jacquie Jacob's picture

Detailed answers to your questions are posted in various places in the blog but I'll try and give you some quick answers to your questions.

Q. How do you know when a chicken is hatched if it is male or female?
A. Depends on the breed and cross. Some specific sex-link crosses make it possible to sex day old chicks on the basis of wing feather size or down color, but only the first day or two and only with the specific sex-linked cross. If you are trained you can sex them by looking at the vent - but it is very difficult to do if you are not trained in it (the variation in possible appearances make it difficult). Otherwise you just have to wait till they get older and secondary sex characteristics develop.

Q. How long can you keep eggs at room temperature or in the nest box if the hen won't brood before incubating them?
A. Depends on the temperature of the room (or temperature in the nest box). The best storage temperature is 50F. When an egg is laid the embryo is already 24 hours old, since that is the length of time that it takes to make an egg. The embryo can go into a kind of stasis until the correct incubating temperature is received. Optimum storage temperature is 50F (which is higher than the typical 45F for a fridge). If the room temperature is too hot (but not incubating temperature, say 75-80F) there can be some embryo development but in most cases deformities occur if the eggs actually hatch. With low temperatures you can keep the fertile eggs for about 1 week without too much loss in hatchability but after that percent hatchability decreases considerably.

Q. What is the best way to incubate without a big expense.
A. You can purchase relatively simple (and inexpensive) styrofoam incubators (most hatcheries sell them) that work well.

Q. If you touch a chicken's egg will it sit on it to brood?
A. Only if she is already going broody - once they are broody they will sit on pretty much anything you give them (brooding chickens have been used for hatching duck and goose eggs, for example). Touching a chicken's egg won't stop them from going broody, but giving them an egg won't make them go broody either.

Hope that helps.

posted on Wed, 09/29/2010 - 7:24am
a nonny mouse's picture
a nonny mouse says:

If you have a healthy rooster with the hens, and he is servicing them, you can pretty much assume the eggs are fertile. After he boinks them a few times, the hens will be producing fertile eggs for up to 2 or 3 weeks, even if you remove the rooster. If you want to hatch some, collect them for a few days, keep them cool, and then start them incubating all at once. After 3 to 5 days, you can candle them to see which ones are developing. And if they are not developing, I wouldn't eat them. They've been at 99-100 deg. F for days. Yuck.

posted on Wed, 06/06/2007 - 10:11am
I have chickens 2's picture
I have chickens 2 says:

We had 17 roosters, well that is a short story even now, we have one now and 17 hens, i took him out of the pen with the hens and put him with my guineas for a while, he was de-feathering them on their backs, they needed some time to heal, so i removed him, I have now put him back because i am fixing to gather me some eggs for hatching babes, so i put him back and i ordered from the hatchery a while back orange beak pieces to fit across his beak,so he cant see straight on, we did this to all our roosters all 17 of them when they were trying to eliminate each other, the one we kept and put with the guineas his fell off after a while, so now i have to put it back on, seeing that I have put him back with his hens so he can fertilize the eggs, because I will gather them in two weeks for incubation, for new babes.I will wait for two weeks that way I know for sure all 17 hens have been with their favorite rooster the only one we have ha ha. All my hens feathers on their backs have grown back now, so i have to put the roosters beak peice back on, or he will de-feather them again.It really just looks bad on my hens and I don't like it when they look like they are all beat up on their backs because i have a over-active rooster that holds them down for awhile.Anyway I will in two weeks put all my eggs in the bators....that do turn and have fans and i keep them the same temp they are suppose to be for 21 days. Then 4 days before the 21st day I take out the ones that are marked the right date.I write on my eggs with a pencil lightly, the date i put them in the bator then on the 17th day i put them in the still bator i call it, they should not turn no more but be still-they are positioning them selves inside to get ready to hatch, with same temp and humidity...make sure the water canal is full always in bator. Then after 4-5 days babes will come, and i let them dry on the screen in the still bator i call it, and then i put then into the infant box that is set up for babes, a water bowl with glass rocks in it so they cant fall in and drown, and a jar lid with scratch feed in it,also a real nice hanging lamp above them that also has to be a certain temp.Then as they get bigger i put them into a bigger box or place ,because i have to have room for the new babes.With guineas you cant mix babes with 2 or 3 week babes the older ones will try to kill them, believe me i know.As for fertilized eggs they are all the same, taste the same and are no different, and are not chickens or babies unless you put them into a incubator then try to eat the eggs later, then you may be eating some chicken in the egg ha ha.The egg has to form and be incubated before its a chicken, its still just an egg, we eat the fertilized ones and the non-fertile ones, they are just eggs.It does matter what you feed your chickens, think about it..I dont agree that commercial eggs and farm raisesd are the same nope! Think about it? It's what you put into the chicken is what comes out and what you eat is what you put into the chicken common sense right? Right! Just like your brain what you feed it comes out of the person...you eat trash , trash comes out, the thoughts and the mouth and the actions.This is all from experience, i do this all the time. If you raise guineas dont and wont to hatch babies dont feed them shell, their eggs are so very hard anyway, i personally had to deliver most of mine from their egg so they would live, they couldnt get out of their shell most of them, not all.So i helped them and now i have over 100 of them and their healthy and happy.

posted on Fri, 02/29/2008 - 8:50am
Mel's picture
Mel says:

ok so my neighbor gave me and my friends these three eggs. he has a coop with a bunch of hens and a couple roosters. and i really want to know if the egg's he gave us are fertilized. he's keeping them unprofessionally too, if that makes it easier for you to help me. he feeds them the right food, but he i don't think he really know's what he's doing. he said that a hen will lay a couple eggs a day and sometimes she won't lay any. so is that just like a natural infertile cycle? or could they be fertilized. it's been about 3 days since he gave them to us. and i tryed the candle thing and nothing showed i couldn't even see the air sac. can you help me out?

posted on Tue, 05/29/2007 - 6:06pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

There is no way to tell if a fresh egg is fertile or infertile without breaking it open. Candling it will only tell you if it has blood spots and how old it is (based on air cell size). Candling is used in verify interior egg quality before selling eggs, especially the large egg producers.

If you can't see the air cell when candling the egg, you may not be doing it correctly. While in a dark room, shine light through the egg. The air cell is typically in the large end of the egg.

If the neighbor has roosters with his hens it is only important that the roosters know what to do - add it does come naturally to them. If there are too many roosters for the number of hens, however, you can get a case where the roosters spend more time fighting with each other instead of mating with the hens.

A hen can only lay 1 egg per day. Birds only have 1 functional ovary, and this is the case for chickens. It takes 24-26 hours for the hen to 'assemble' an egg (from the time that the ova/yolk is released from the ovaries to the time that it is laid). If eggs are not collected at the same time each day, you may have a case where a farmer collects eggs early one morning and then late the next day. In such cases they could end up picking of more eggs than normal.

You can eat the eggs whether they are fertile or not. You only need fertile eggs if you are going to be incubating the eggs.

Hope that helps.

posted on Wed, 05/30/2007 - 1:28pm
Ed's picture
Ed says:

Can I get a list of classes that Dr. Jacobs teaches. There are no upper division classes to be found in California.

posted on Sun, 07/15/2007 - 11:21pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Kentucky - Poultry extension specialist

When I was at the University of Minnesota I taught four poultry related classes, but none were available on the internt:
Avian Sampler - covers a wide variety of topics related to birds. While there is some poultry, a wide variety of avian related topics were covered.
Poultry Management - pretty much what it says.
Poultry judging - to prepare a team for the national collegiate poultry judging contest in Baton Rouge, LA in April.
Advanced poultry judging - to prepare a team for the national collegiate poultry judging contest in Fayetteville, AR.

Now that I am no longer at the U of MN (currently at the University of Kentucky with no teaching appointment) none of the above courses will be taught.

If you are looking for more advanced poultry-related courses, you might consider the Midwest Poultry Consortium which offers 6 poultry courses - students take three each of two summers (6 weeks for the 3 courses each summer). There are scholarships available - but only for students in the 13 midwest states and Florida, since they participate in the program. You could go and pay your own way I suppose. Applications are taken in early spring.
Their website is http://www.mwpoultry.org/
An article discussing the program is also available online at http://ps.fass.org/cgi/reprint/77/2/211.pdf

posted on Mon, 07/21/2008 - 12:07pm
Anonymous's picture
Anonymous says:

i have a question. i hens and roosters together. i have a verity of different chickens . one of them are araccans. they lay differentcolored eggs. this egg i dicovered was still warm so i took it in and put it under a heat light to try to hatch. not sure if it is fertile because it is a darker colored egg and you can not see through it if you hold it up to the light.. as you call candled it... Do i just wait for 21 days or do you think im wasting my time because it is not in an incubator.. do you think it will hatch under a heat lamp or regular light?????

posted on Tue, 03/17/2009 - 10:21pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Kentucky - Poultry extension specialist

I assume you mean you have Ameraucana chickens? Araucana chickens lay green/blue eggs, have no tail and tufts of feathers protruding from their face, near the ear lobes. Ameraucana's are a cross between an Araucana chicken and another breed. The gene for the egg color comes through - but they have tails and instead of ear tufts they have a fluff of feathers around the 'chin' and neck called muffs and beards.

The egg was still warm since it had recently been laid. You can't tell if an egg is fertile or not by just holding it up to a light (also called candling). The only way to tell for sure is to incubate them. You can tell if you break them open, but then you can't incubate them.

A heat light is probably insufficient for proper incubation of the egg. The require the right temperature and humidity and need to be turned regularly (minimum of three times per day, in a different direction each time so that you are not just rotating the egg in circles). It is POSSIBLE that the egg may hatch, but if it does the chick likely to have abnormal development. You really do need an incubator. They do make small incubators that can hatch 3-10 eggs at a time. They can be purchased online.

Hope that helps.

posted on Wed, 03/18/2009 - 9:54pm
Tim the Enchanter's picture
Tim the Enchanter says:

It's actually a vegetarian issue. Some vegetarians will eat non-fertilized eggs, but fertile eggs are off-limits. And of course, in that case, you wouldn't eat the adults either.

posted on Thu, 08/09/2007 - 9:22am
Anonymous's picture
Anonymous says:

hi i am a vegatarian and i am a dairyoan that means i dont eat fish pultry(cause of my darling 4 hens and 1 rooster) or meat and i eat my chicken eggs ALL the time but thats just me

posted on Tue, 04/22/2008 - 4:41pm
Todd Elliott's picture
Todd Elliott says:

how many eggs can a chicken lay per day? I've heard that farm raised can lay 2 a day.

posted on Mon, 10/09/2006 - 12:15pm
Liza's picture
Liza says:

It depends on a variety of different conditions, from the breed of the hen to her health and diet to the length of the day. Generally speaking, it takes about 24 hours to lay an egg, but there are certainly exceptions to that.

posted on Wed, 12/27/2006 - 5:19pm
Anonymous's picture
Anonymous says:

why is it not good to eat a egg with blood in it?

posted on Sun, 05/13/2007 - 11:53am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

There is no problem with eating an egg with blood in - it gives you a bit more protein (from the blood). They candle out eggs with blood because of the appearance - consumers don't like to see blood in their eggs.

posted on Wed, 05/30/2007 - 1:30pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Birds have only one ovary and oviduct and it takes 24-26 hours to assemble an egg, so hens can not lay more than one egg a day. If, however, you don't collect eggs at the same time each day you may find 2 eggs from one hen - but they were laid 24 hours apart.

posted on Tue, 04/10/2007 - 12:29pm
Anonymous's picture
Anonymous says:

Dr. Jacob,
I have been keeping chickens for some time and have seen all sorts of strange eggs. But I came across one yesterday that has me baffled.

Background: Our eggs are gathered several times a day and nests are checked at night when the hens are locked up. So there is NO possibility this egg had time to incubate. (and yes, we a have a rooster, so fertilization is likely)

So I gathered some eggs from the nests and took them inside to clean them. I was cleaning one that was a little thin-shelled and it broke. Inside was a dime sized mass that appeared to be a developing embryo.

How is this possible? Or what could it be if not an embryo (I dissected it and would say it is an embryo- though I don't have much experience identifying stages of development). I wish I had taken a picture now.

Thanks,
DCN

posted on Mon, 07/05/2010 - 8:31am
Jacquie Jacob's picture

It could have just been a very large blood spot. I have seen some pretty big ones over the years. The fact that it was thin-shelled could indicate a problem with 'assembly' of the egg - but not all thin shelled eggs have blood spots and not all blood spot eggs have thin shells.

A dime-sized embryo would take several days to form and I can't see that happening inside a chicken prior to being laid.

My money is on the blood spot.

posted on Tue, 07/06/2010 - 5:40am
Anonymous's picture
Anonymous says:

Can you eat fertilized eggs? My sister-in-law had someone give her some and doesnt know if she should eat them or if it would be like eating "baby chickens".

posted on Mon, 10/09/2006 - 6:28pm
Cat's picture
Cat says:

I think you can eat them, it's not poisonous is it? Some cultures even eat "baby chickens". If it hasn't been hatched/incubated: I'm sure it will still taste somewhat the same. Besides, if you're hungry you're hungry. If you don't eat it, it will rot and be wasted if you don't hatch it anyways. Hatch it and raise them, hatch it and eat them after you raise them, or eat them.

But if one has no mouth, eating an egg is impossible.

posted on Wed, 10/18/2006 - 2:18am
Liza's picture
Liza says:

You can eat them. Some people even prefer them.

posted on Wed, 12/27/2006 - 5:19pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

You can definitely eat fertile eggs. As you can see from these photos, fertile and infertile eggs look very similar and you wouldn't be able to tell the difference without looking closely, unless the eggs have been incubated, of course.

There are some people who pay a premium price to get fertile eggs for consumption, while others will not eat them at all. It is a personal preference.

There are some cultures that eat embryos, especially duck embryos. A food product called balut is produced by incubating duck eggs till just before the embryo develops feathers (about day 18 of the 28 day incubation period). The embryo is boiled in the shell, salted and eaten. It is very popular in the Phillipines and Vietnam.

For more information on 'fetal duck eggs' see:
Wikipedia entry
Deep End Dining

posted on Tue, 04/10/2007 - 12:39pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

You can eat eggs whether they are fertile or infertile - there are nutritional or food safety differences between the eggs. In the fertile eggs the embryo is about 24 hours old when it is laid (since it is fertilized at the top of the oviduct and it takes 24-26 hours to complete the assembly of the parts of an egg so it can be laid). You really can't see the embryo without a magnifying class. If properly refrigerated the embryo will not develop any more at all.

If you feel that life begins at conception, then in theory you are eating 'baby chickens' but if the egg is not incubated the embryo will never develop into a chicken. So it is up to you whether or not you want to eat fertile eggs. I have friends that will never eat fertile eggs, since it 'grosses them out.' I personally have no problem eating fertile eggs - but all eggs in the typical grocery store are infertile unless otherwise indicated.

posted on Wed, 05/30/2007 - 1:35pm
Jadie's picture
Jadie says:

Hey
I saved a egg from a tree that had been cut down, i don't know what type of egg it is but its small and a pure white colour. I have wrapped it up and placed it in the airing cupboard but i don't know if it is alive or not. It was cold when i first found it but it feels warm now. I want to look after it until it hatches but firstly i need to know if it will hatch. This site said leave it for 21days. Is there anyway to tell if it is alive? Do you think it is alive?
Thanks, any comments would be appriciated

posted on Tue, 10/10/2006 - 1:05pm
Liza's picture
Liza says:

Jadie,

I passed your question along to Dick Oehlenschlager, the museum's biology collections manager. He said,

"I really can not say much here, without more information. Letting the egg sit by itself for 21 days certainly will not induce the egg to hatch. I would say there is no or next to no chance for it to hatch, and there is no point in trying to make it happen. Since many or most cavity nesting species lay white eggs, and I don't know how small the egg is, I can only suspect woodpecker, tree swallow, small owls,etc. It is also illegal to possess eggs of these species (regardless of the circumstances under which they are found) and permits from federal and state agencies to do so are not issued to individuals, only scientific or educational institutions."

Sorry.

posted on Fri, 10/20/2006 - 9:43am
Anonymous's picture
Anonymous says:

Yes but i once found a egg that was cold but ti still hatched. explain that?

posted on Sun, 04/01/2007 - 5:16am
Melissa's picture
Melissa says:

Because the hen can only lay an egg every 24 hours, eggs need to have a dormancy period. Let's say that it takes the hen 10 days to lay a clutch of 8 eggs... during those 10 days, the hen will turn them but not keep them warm. Without warmth, the embryo will not develop. I *believe* the eggs can remain dormant for about 30 days (though after 10 days, chance of hatching begins to decrease). Theoretically, the eggs would have to endure cool temperatures during this time. After the 10 days, the hen would set on them, providing the constant turning, temperature and humidity we mimic with an incubator for 21 days, and all the eggs would hatch at the same time.
So, provided your cold egg was dormant when you started the incubation period, there shouldn't have been a problem.

posted on Sat, 06/02/2007 - 1:48pm
Anonymous's picture
Anonymous says:

hold the egg to a bright light after about 10 days then you should see a feoutus inside if the eff is fertile then the chances are it wil hatch and die in a couple of days as it is very hard for an inexperienced person to feed a chick if it hatches contact me and i tell u how to raise it my email is mwgriffin@hotmail.co.uk

posted on Fri, 10/27/2006 - 7:32pm
Anonymous's picture
Anonymous says:

if the chick dies can you eat the egg ?

posted on Sat, 11/04/2006 - 9:57pm
Liza's picture
Liza says:

I wouldn't.

posted on Wed, 12/27/2006 - 5:20pm
Brad's picture
Brad says:

Thanks two of my buddies and I had an ongoing argument about this for the last two months and this web page has proven me right about hens laying eggs without roosters

posted on Thu, 10/19/2006 - 10:04am
jadie's picture
jadie says:

Hi
Thanks to all who answered, i took the egg to my sixth form and the science teacher held it up to a light and claimed that it was a fertile egg and he took it to look after it, we don't know what type of egg it is yet but my teacher is looking in to it. He said that it definatly isnt a woodpecker egg or a tree swallow and that it isnt illegal for us to look after it until it hatches, once he knows what type of egg it is however he is going to hand it to a bird sactuary (not a scientific or educational institution) as i agree that both he and i arent experienced enough to look after it and we do want it to survive. However when it hatches and if it survives i want to release it back to the wild.If it hatches i will send you all photos.

posted on Sun, 10/29/2006 - 11:17am
Liza's picture
Liza says:

From references to "sixth form" and also your spellings of certain words, I'm going to assume you're writing to us from outside the US. Dick Oehlenschlager, our biology collections manager, was assuming you were writing from somewhere in the US. And here it IS illegal to collect the egg of a migratory bird.

But we'd love to know what happened: did the egg hatch?

posted on Wed, 12/27/2006 - 5:22pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

You can find more information on the Migratory Bird Treatry Act online

According to the act, it is illegal to possess any migratory bird, part (which includes feathers), nest, egg or product.

The only birds in the U.S. that don't fall under this act are pigeons, sparrows and starlings, since these species are not native to the U.S. They are introduced species (and in some cases have become nuisance birds).

posted on Thu, 05/24/2007 - 12:28pm
Chasity's picture
Chasity says:

My rooster and my sister's hen are together all day and everyday. And we don't know if our hen is pregnant or not. What are some signs of her being pregnant?

posted on Mon, 11/27/2006 - 3:21pm
Liza's picture
Liza says:

According to the Mississippi State University Extension Service,

"If a sexually active rooster is placed into a flock of hens, fertile eggs can be produced by the second day after introducing the rooster. If mating occurs within a short period, the next egg yolk released by the hen's body can be fertilized. The remainder of the albumen and shell requires about 26-28 hours to be formed around the fertilized yolk. Therefore, a minimum of 30-36 hours is necessary to produce a hatchable egg.

If the flock has many hens and only one rooster, it may require several days before mating with all hens takes place. It is advisable to allow at least 4-7 days before expecting a high level of fertility in eggs. If the rooster or hens are one-year or more in age, the waiting period may need to be increased."

But your hen won't ever be "pregnant." If the hen and the rooster have mated, then sperm are in her reproductive tract, waiting to be incorporated into the next egg she lays. If not, the hen lays eggs anyway, but they aren't fertilized. Development of the chick happens inside the egg, but outside of the hen's body.

It sounds, though, like maybe your hen isn't laying eggs at all? Egg production is dependent on how much daylight the hen is exposed to. If you want her to lay eggs, she needs at least 12, and preferably 14, hours of daylight or its equivalent each day.

If she's laying, and she's with the rooster all the time, she's probably laying fertilized eggs.

posted on Mon, 11/27/2006 - 4:00pm
Wilbur Oxley's picture
Wilbur Oxley says:

I am a farmer in rural Misssouri and my chickens haven't laid a single fertile egg since I introduced a rooster among them last month. Could I have me an infertile rooster?

posted on Wed, 12/27/2006 - 9:02pm
Anonymous's picture
Anonymous says:

I have been told that when you introduce a new bird or move birds to a new home it can take a month for them to be realy settled. Wait a little longer. If you see him mating with the hens and leave the eggs in the nest to pile up and eventually the hens should get broody and start laying on the eggs. I have never had chickens before but got a cockerel and a hen. I followed this advice and today i have chicks hatching.

posted on Thu, 03/08/2007 - 8:36am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Fertility is affected by a number of factors - some affect female fertility and others affect male fertility. You can actually 'milk' a rooster to collect semen and examine it under a microscope ot see if it contains active sperm.

How old are the hens and rooster? Age (too young or too old) can affect fertility.

What type of lighting program have they been exposed to? Roosters, as with hens, are long day breeders in that they breed when days are long (more than 12 hours).

You also need to look at the ratio of males to females - optimum ratios depend no breed but are typically 1 male to every 5-6 females.

How have you found that they are infertile - by opening them or incubating them? If incubating them, you might have fertile eggs with very early death because of storage conditions prior to incubation and conditions during incubation.

posted on Tue, 04/10/2007 - 12:53pm
Heather's picture
Heather says:

Hello,
I have just discovered that one of my chickens has a secret nest with 10 green eggs. She sits on it infrequently. I brought the eggs to the house and tried to "candle" them. I can use my imagination and say that there is a dark disc on one end of each egg, but it's the same spot on each egg, so it could be just that -- my imagination. I broke one open and saw a whitish circle pattern that you had described. My question -- if they are fertile, how much time should the hen spend on the eggs? She leaves them alone all night and I see her all over the place, not on the nest. They are small eggs and her first ones ever. They are cold when you pick them up. If they are not going to survive because she is not sitting on them, should I borrow my daughter's teacher's incubator and give it a try? Is it too late (maybe a week old)? Are they going to be not fit to eat?

posted on Tue, 04/17/2007 - 8:43am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Once a hen starts incubating her eggs, she sits on them most of the day, leaving only to get something to eat. She will wait till she has finished laying her 'clutch' of eggs (the number of eggs she is going to incubate) before she starts incubating on them - so they will be cold to the touch. It may not be too late to incubation artificially. You could incubate for a week and try candling them again to see if there are any embryos in them. You should be able to see them by then, though it is more difficult with green eggs.

posted on Thu, 04/26/2007 - 5:02pm
Anonymous's picture
Anonymous says:

hi i am 11 years old and have 4 hens and 1 rooster this question is for Dr. Jacquie Jacob
i have an incubator and i am going to hatch eggs BUT i don't know if all my eggs are fertile and my chickens just got a dose of medicine to clean there systems so i have to wait till thursday to incubate but can i use eggs from last week that are sitting in the kitchen in a basket outside of the reridgerarator please email me

posted on Tue, 04/22/2008 - 4:57pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

It is impossible to tell if the eggs are fertile without breaking them open - so incubating them and then candling at about 7 days to see if there is an embryo or not is the only real way to know.
Eggs stored in a fridge typically have reduced hatchability, especially after 1 week. Hatching eggs are typicallly stored at 55F while most fridges are at 45F, which is too cold. You can try though - it doesn't mean you won't get any chicks hatch, just the percent of eggs that hatch will probably be lower than if stored at the correct temperature or for a shorter period of time.

posted on Tue, 04/22/2008 - 6:01pm
Kelly's picture
Kelly says:

Hi, my question is, is it true that if you touch an egg in the nest, the hen will no longer touch it or look after it?

Thanks.

posted on Wed, 01/03/2007 - 7:15pm
Theresa's picture
Theresa says:

I am a novice at this but i know the answer as my three year old took two of the eggs from under my chicken. i made her put them straight back. The chicken is still laying on all the eggs as she should be. But from what i have read its not great to touch them as our hands can spread germs to the eggs.

posted on Tue, 03/06/2007 - 7:39am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Depends on the temperament of the chicken and whether or not she has gone broody. If the hen is broody, periodically touching the eggs shouldn't be a problem. I have had hens go broody with no eggs and added my own - they are pretty good for incubating duck and geese eggs as well as chicken eggs.

posted on Mon, 05/14/2007 - 2:50pm
Anonymous's picture
Anonymous says:

hi sorry to comment so much but...
is it possible to get a red layer chicken to go broody? and how please email me

posted on Tue, 04/22/2008 - 4:59pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Broodiness is hormonally controlled so there really isn't much to induce it - different breeds having different tendencies to go broody. You don't indicate the breed you have - and may not even know it if it is a cross-bred so it is hard to say what the likelihood is that she will go broody.

Most people are trying to stop hens from going broody - I don't know of any efforts to cause a hen to go broody - most just usually invest in a breed that easily goes broody.

posted on Tue, 04/22/2008 - 6:07pm
Anonymous's picture
Anonymous says:

this site is so interesting! When I started reading about fertilization, I was amazed! I always thought that if you were to sell eggs to a grocery store, they would have to be fertilized. But it's really interesting to find out that you can't sell fertilized eggs at the market because if they're fertilized,a chick will form during incubation. thanks for the great info dude. by the way i'm a girl i just like saying dude a lot!

posted on Thu, 01/11/2007 - 9:38am
craig's picture
craig says:

hi I just wondering if I had a fertilized chicken egg and I decided wether to put it in an incubator in three months or so will the egg still be fertilized and hatch? or will it not? if so how long have I got until the egg is not fertilized. Thanxs

posted on Sat, 01/20/2007 - 12:21am
Liza's picture
Liza says:

Once fertilized, always fertilized. However, after three months, that egg is no longer viable and will not develop even if you put it in an incubator.

posted on Sat, 01/20/2007 - 9:59am
Anonymous's picture
Anonymous says:

I have heard that you can only eat eggs from chickens for a ceteian number of days, 74, I believe is what I was told. After this certain time you have to get new chickens to get edible eggs. Is this true?

posted on Fri, 01/26/2007 - 7:26pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

You can eat the eggs from chickens of any age. Hens typically start laying eggs at 18-20 weeks of age. They will continue to lay for several weeks, increasing production levels quickly, peaking and then slowly reducing production levels till production reaches a level where it is typically not economical to keep them in lay. This is usually around 60-70 weeks of age.

In commercial operations producers may put their hens through a 'molt' which is forcing them to take a break and stop laying. After a few weeks they come back into production at a higher level than before the rest was initiated.

Alternatively, the older hens can be replaced with new pullets which are just starting their laying cycle.

You can find more information on egg production online.

posted on Tue, 04/10/2007 - 1:01pm
Anonymous's picture
Anonymous says:

Im not sure that my young hen is a hen. How can I tell the difference ? It is about 6 months old and looks like small spers on the legs with long tale feathers.

posted on Sat, 02/03/2007 - 5:56pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

By 6 months of age most chickens have taken on the typical characterists specific to male and female. Males have long pointed feathers around the neck, shoulder and tail. Their combs and wattles are larger than those of females. (The comb is the fleshy material on the top of the head and the wattles hang down from the throat. Both sexes have them, but they are bigger in males than in females). Males also typically have larger spurs at the back of the leg.

By six months of age, if your chicken is a rooster, it should be crowing by now.

Of course, to complicate things, it is possible for a hen to take on the characteristics of a rooster, due to hormonal problems (PDF).
This same website shows the difference in feather structure of males and females.

posted on Tue, 04/10/2007 - 1:33pm
Anonymous's picture
Anonymous says:

I'm glad you mentioned that hens can take on characteristics of a rooster. We purchased a pair of ''show chickens'' that we named Rudy and Judy. Clearly obvious who was who, sex wise. Beautiful birds, very sweet pets. Eventually we were given other hens. Rudy and Judy both, did the side-stepping around the other hens, mounted the other hens and Judy clearly ''crowed'' with the best of roosters. We took her to our Vet., who stated she was clearly a hen! She never laid an egg. She had a long and happy life, confused, but she was a doll:)

posted on Mon, 06/30/2008 - 11:09am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Kentucky - Poultry extension specialist

I know of a 4-Her who entered a chicken in a county fair in Florida two years in a row and won both times - the first as champion hen and the second as champion rooster.

posted on Tue, 07/01/2008 - 9:41am
Anonymous's picture
Anonymous says:

how do you tell the difference between a rooster and a chicken when they are young

posted on Sat, 02/10/2007 - 10:04pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

It is very difficult to tell the difference between male and female chicks. Often it takes specially trained technicians to sex them, using feather and vent sexing techniques (PDF).

According to Keith Bramwell at the University of Arkansas:

"All in all, the best way to sex chickens in the backyard flock is to watch them grow. Feed them, water them, observe them and enjoy them while they mature. As they develop, changes will become obvious as the males will begin to act manly and their voices will change from the chirping common to young chicks to attempted crows. In nearly all breeds of chickens (Sebrights being the exception) the young males’ feathers will also change from the round oval-shaped feathers common to hens and young birds to the shiny, more narrow and pointed feathers found on their necks and at the base of their tails.
While a number of 'old wives tales' exist about sexing chicks, these methods are no better than flipping a coin. While feather sexing and vent sexing are accurate methods of determining the sex of chicks, perhaps the best and most enjoyable method is just watching the birds grow."

posted on Tue, 04/10/2007 - 1:46pm
Anonymous's picture
Anonymous says:

A rooster has that thing hanging below their throats.

posted on Sun, 02/11/2007 - 12:28pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

I believe you are referring to the wattles. Both hens and roosters have wattles, they are just larger on males.

More information on chicken anatomy

posted on Tue, 04/10/2007 - 1:47pm
Anonymous's picture
Anonymous says:

hey, i have a pair of chinese silkies, a rooster and a hen! Just over three weeks ago the hen was showing broody behaviour. over the weeks i observed her, she stayed on the egg most of the time only coming out once to eat/drink. however she only was sitting on one egg! the other hens weren't laying very often at this time, as she scared them off!!!
For the last two days she stopped sitting on the egg. previously i didn't get the chance to check the egg by light, as she would peck me and make funny noises.
I Cracked the egg and oh no.... there was a little chick inside! why did she stop sitting on the egg? can hens tell weather the baby is alive or not, or did she loose interest?
i'm pretty new to all of this, cause in the past we haven't keep a rooster for very long as they can be violent!!! Now i know to keep the hen away from the other hens, to decrease any distractions.
any advice would be appreciated! thanks Nicole.

posted on Thu, 03/01/2007 - 1:02am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

The broodiness of chickens is affected by the bird's hormones. Sometimes things go wrong and the hen stops sitting on eggs she was previously incubating. When the embryo is young it is hard for the hen to tell if it is alive or not, but once it gets older the embryos make noise that the hen can hear. In fact, embryos in the eggs next to them have also been shown to hear their 'siblings'.

From an Oregon State factsheet (PDF):

"Broodiness is the natural tendency for a hen to sit on her eggs to hatch chicks. Most hens eventually go broody, some breeds more often than others, although some breeds rarely, if ever, go broody. (Cochins and Silkies are champions at going broody; broodiness is rare in Leghorns.) When a hen becomes broody, hormonal changes result in the cessation of lay.
The stimulus for broodiness normally is a nest full of eggs; however, some hens will go broody without this stimulus. To reduce broodiness, collect eggs daily from nests and hiding places. If a hen shows a desire to stay on the nest for extended periods, remove her from access to the nest for several days. After a period of time, the broody behavior will cease and she will return to egg production."

posted on Tue, 04/10/2007 - 1:53pm
Anonymous's picture
Anonymous says:

I am confused about my hen. She is a brown Leghorn and is very sweet and follows me everywhere but she lays an egg one day then sits on it overnight then stops and lays another one and only sits on them randomly at night. My neighbor told me chickens lay a certain amount of eggs, then incubate them- but i'm still pretty confused.

posted on Sun, 03/04/2007 - 7:08pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Leghorns do not go broody very often - removing the eggs daily will stop the behavior (unless of course you are trying to get her to hatch some chicks).

She may simply like the darkness of the nest and that could be attracting her to sit on the nest overnight rather than broody behavior.

More information (PDF)

posted on Tue, 04/10/2007 - 1:55pm
Anonymous's picture
Anonymous says:

Is there any other way to tell if the egg has been fertilized, other than candling?

posted on Tue, 03/06/2007 - 6:21am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

You can't tell whether or not an egg is fertile by candling. You can only really do it by breaking it open (and then you can't incubated it) or incubating the eggs to see if an embryo develops (which you can see by candling the egg at 2-3 days of incubation).

posted on Tue, 04/10/2007 - 1:57pm
Anonymous's picture
Anonymous says:

We moved to the country and got a chicken and rooster. He has definately mated with her. She started to lay eggs and as we wanted chicks i left the eggs in the nest. After 17 days and seventeen eggs she started laying on the eggs. It was very cold/ snowy for the first week she was laying eggs, so i do not think the first few eggs are any good. She gets off once a day about lunchtime for 15 minutes and goes off for a wonder and a feed. I didnt make a note of the date she started laying on the eggs but i am sure it must be nearly three weeks. I do not know if the eggs are fertile. Will she continue to lay on the eggs for many weeks if they do not hatch and if so how long should i leave it before removing the eggs?

posted on Tue, 03/06/2007 - 7:31am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Chickens have been known to sit on eggs well past the 21 day incubation period. There are breed differences in this behavior. If the eggs haven't hatched by 25 days, while she is off getting something to eat you can candle the eggs and see if there are embryos inside. That will help you decide whether or not to continue or to remove the eggs before they start to smell.

posted on Tue, 04/10/2007 - 1:59pm
Anonymous's picture
Anonymous says:

dear Dr. Jacobs i have 4 hens they take turns one chicken lays for one week then another for another week somtimes the fattest one lays for two weeks why they are 7 months old

posted on Mon, 02/21/2011 - 7:07pm
Anonymous's picture
Anonymous says:

i got three chickens i dont know which ones are laying but i check all the time i dont see any of the laying on the eggs what do i do

posted on Tue, 03/06/2007 - 11:15am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Depending on how long the hens have been laying, you can do a physical examination to see which of the hens are laying (they all may be laying, just not at a high enough rate to have 2-3 eggs/day).

Evaluation of laying hens

Photos related to evaluation of laying hens, especially those breeds with yellow skin (such as Leghorns) (PDF)

posted on Tue, 04/10/2007 - 4:01pm
Theresa's picture
Theresa says:

I posted a question on 3/6/07 re my chicken laying on her eggs. I will not have to remove them as they started hatching today. I can hear some chicks and some sounds like pecking at a shell. Dora wont get off them at the moment so i dont know how many of the seventeen have hatched. I am assuming the dad wont harm his babies? There is only him and the mum and now the babies.

posted on Thu, 03/08/2007 - 8:27am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

The rooster shouldn't hurt the chicks - but it is temperament thing. There are occassions when the rooster will attack the chicks, but most times the hen is protective and won't let him.

posted on Tue, 04/10/2007 - 4:53pm
Jo Ann's picture
Jo Ann says:

My husband and I have just started a chicken coop and have several hens and one roo. My question to you is: Why is only one of the hens laying eggs and not the rest? Could we do something to help this process? Please advice.

Need all the help we can get,

Jo Ann

posted on Thu, 03/08/2007 - 9:16am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

A number of factors could be involved - anything from genetics, management to nutrition. See this factsheet from the University of Vermont and another from Oregon State University.

posted on Tue, 04/10/2007 - 5:00pm
Anonymous's picture
Anonymous says:

is there a type of hen egg that do not have any yolk? only egg albumen?

posted on Thu, 03/15/2007 - 3:50am
Anonymous's picture
Anonymous says:

Interesting question. I don't think so because the embryo needs an energy source, but curious to the answer.

posted on Thu, 03/15/2007 - 10:02am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

It is not typical to have an egg without a yolk but it can happen. Sometimes a little piece of the oviduct is sloughed off and starts to travel down the oviduct and the hen adds albumen, shell membranes and a shell and the 'egg' is laid without a yolk.

Since the female genetic material is on the yolk, and the yolk provides nutrients for the embryo to develop, a chicken that always lays eggs without a yolk would not be able to reproduce.

You can get all sorts of abnormal eggs - I have even seen eggs with complete (but smaller) eggs inside.

posted on Tue, 04/10/2007 - 5:02pm
applevgame1's picture
applevgame1 says:

Again interesting question... i don't know

posted on Thu, 03/15/2007 - 11:03am
Shae's picture
Shae says:

for those of you wanting to know about the fertilization of an egg and how long you can hold it, the chances of hatching the egg goes down alot after seven days of holding the egg. if youre going to hold it before you are going to incubate it then you need to store it at around 50 degrees. the reason they say to hold it is so you can collect all the eggs that you want to incubate and start them in the incubator at one time. Just becareful not to wait to long... give it a try though its fun!!!

posted on Wed, 03/21/2007 - 7:53am
Tammy's picture
Tammy says:

We have hens and roosters, we seperated the hens and roosters for a brief time due to large amount of feathers missing from hens back. Probably a week has gone by and one of the hens is sitting on her eggs, are these eggs fertile?

posted on Wed, 03/21/2007 - 8:13am
Liza's picture
Liza says:

They might be. Surf the rest of this thread for some ideas on how to tell if your chicken's eggs are fertile.

posted on Fri, 03/23/2007 - 12:49pm
Crystal's picture
Crystal says:

I have a few hens and one rooster that walk around my yard every day. My parents and I have come across a spot where the hen has been laying her eggs. Well for the first time today, we've noticed she's actually sitting on them. A friend of my parents told my mother that the hen didn't have to be fertilized by the rooster in order to have chicks. Basically saying, that hens don't reproduce to have chicks. Isn't that wrong? Hens have to encounter a rooster to fertlize the eggs to have chicks, am I correct?

posted on Thu, 03/22/2007 - 6:39pm
Liza's picture
Liza says:

A hen must be fertilized by a rooster to produce chicks.

But hens will produce eggs (unfertilized ones, which can never develop into chicks) without contact with a rooster.

So you can get eggs either way, rooster or no, but you'll only get chicks if the rooster and the hen are together.

posted on Fri, 03/23/2007 - 12:47pm
Anonymous's picture
Anonymous says:

HI THINK CHICKEN IS THE POPULAEREST ANIMAL FOR TO EAT BECAUSE THE PROTIAN IN THE EGGS I MYSELF DON'T HAVE ANY CHICKENS OR HEN BUT I KNOW THEY CAN TO NOISEY SOMETIMES MAKE THE SOUNDS THEY DO MAKE HENS HAVE TO ENCOUNTER A ROOSTER TO FERTLIZE THE EGGS TO HAVE CHICKS, AM I CORRECT OR AM I WRONG.

posted on Fri, 03/23/2007 - 12:30pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

You are correct - a hen has to be with a rooster to have fertile eggs and thus chicks.

BUT a hen will lay eggs (infertile) without the presence of a rooster.

posted on Tue, 04/10/2007 - 5:06pm
Anonymous:D's picture
Anonymous:D says:

how many eggs does a chicken produce each time? :D

posted on Sun, 03/25/2007 - 7:00pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

A hen produces one egg at a time since she has only 1 ovary and 1 oviduct. It takes 24-26 hours for her to assemble and lay an egg. Shortly after she lays an egg, she ovulates another yolk and the process begins all over again.

Diagram of a hen's oviduct

posted on Tue, 04/10/2007 - 5:10pm
Anonymous's picture
Anonymous says:

My hen is young, about 9 or 10 months. She just started laying for the first time. She has layed about 5 total,
but has eaten one or two and the rest come out not completely formed like an egg. Kind of gooey. but she is protecting the same egg. This one egg she sits on throughout the day and night. But won't keep any other egg in the nest. Is this normal for a first time layer?

posted on Tue, 03/27/2007 - 9:08am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

It sounds like your hens are suffering from a calcium deficiency and thus are not able to create a strong shell (which is made up of calcium carbonate). You need to check and see what she is being fed - it needs to be a laying hen diet with sufficient calcium. You can also add oyster shell to her feed to increase calcium consumption.

posted on Tue, 04/10/2007 - 5:12pm
Kenny's picture
Kenny says:

How long can one keep setting eggs out before they put them in an incubator and still produce a hatch?

posted on Fri, 03/30/2007 - 8:20am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Avian embryos are unique in that they stop development between when they are laid and when they are incubated. This allows the hen to lay several eggs before sitting on the group to incubate them.
If stored at the correct temperature, hatching eggs can be stored for 2-3 weeks - but hatchability starts to decrease after the first 7 days of storage.

posted on Tue, 04/10/2007 - 5:16pm
Rowdy's picture
Rowdy says:

How lon can I keep eggs setting out before I have to put them in a incubator and they will still hatch. I appreciate you help.
Thank You
Rowdy

posted on Sun, 03/23/2008 - 8:51pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

It depends on how the eggs are stored - they should be stored at 55F, which is higher than most refrigerators were are usually run at 45F. In addition, because of the humidity in refrigerators eggs will dry out if eggs and reduce hatchability.
It also depends on what type of eggs - I'll assume you mean chicken eggs. Then a 10 day limit is best - much more and your percent hatchability will go down considerably.

posted on Mon, 03/24/2008 - 10:28am
Hannah's picture
Hannah says:

A hen started pecking at her eggs and made a hole in it and gooey stuff is coming out. Why did she do that?

posted on Tue, 04/03/2007 - 7:57am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Not sure what you mean by 'gooey stuff' - just sounds like the contents of the egg.

Egg eating can be a problem. It is sometimes started because of a nutrient deficiency but it can also be started for no particular reason at all. Chickens are attacked to shiny objects - If an egg gets broken they will start pecking at it, and eventually eat it. For some hens, once they get a taste of eggs they start breaking eggs to eat them. It can be a hard habit to break.

More information (PDF)

posted on Tue, 04/10/2007 - 5:19pm
Alex and Sabrina's picture
Alex and Sabrina says:

My aunt has chickens of her own, and I never knew that much about them. But thanks to this program, I found out a lot of cool information. Thanks a bunch!!

posted on Tue, 04/03/2007 - 10:55am
whatdoidonow's picture
whatdoidonow says:

well my chicken laid 2 eggs today and she doesnt have a mate. Could someone please let us know what to do know. For examle do we just leave it alone or do we have to do a certain something?

posted on Sat, 04/07/2007 - 8:21pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

If there is no rooster for your hen the eggs will be infertile. You can consider them a gift and eat them. If you leave the eggs with the hen they will get old and can turn rotten (very smelly if they become rotten and break).

posted on Tue, 04/10/2007 - 5:20pm
Terry's picture
Terry says:

I have a pet a hen...I have no rooster but there are roosters in the neighborhood...I just today noticed that she has made a nest and it contains 4 eggs...1 egg per day means she most likely started laying 4 days ago...Since they are most likely not fertile and at least 4 days old can they still be collected for eating or have they been out too long? Also...If I take them away will she continue to lay?

Thanks!

Terry

posted on Sat, 06/07/2008 - 9:45pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

The hen will most likely continue to lay after you take the eggs away, unless she has gone broody.

Food safety-wise I wouldn't recommend eating the eggs, but it depends on a lot of things - temperature where the eggs are (especiallly maximum during the day), how dirty the eggs and nest are, and whether the hen has been actually incubating them.

posted on Tue, 06/10/2008 - 9:43am
Anonymous's picture
Anonymous says:

I bought chicks from the pet shop and i hand raised them. they are about 3 months old and they are leghorns but i dont know which one is a rooster and which one is a chicken. when i bought them the guy told me that the white leghorn is a rooster and the greyish white leghorn is a chicken. the white leghorn always puffs up when he sees the other chicks. the other leghorn doesnt mind. can someone help me if i send a picture or is it still to early to predict.

posted on Sun, 04/08/2007 - 5:26am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

You should be able to tell pretty soon. They are sexually mature at 17-20 weeks which is 4-5 months.

Paintings of different leghorn varieties

posted on Tue, 04/10/2007 - 5:28pm
Penny's picture
Penny says:

Ok, my daughter and her friends made an incubator for thier science fair project. We have never actually tryed the incubation before, but we don't know how to candle an egg. This is the 16th day in the incubator and we don't know what we are to do.

posted on Sun, 04/08/2007 - 9:17pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

By now the embryo should be close to hatching (21 day incubation period and they were at 16 days 4 days ago) so too late to candle this time.

For next time check out the following websites:

"Candling chicken eggs"
"Candling eggs"
"Candling Pictures by The Easy Chicken"

posted on Tue, 04/10/2007 - 5:38pm
19kitty91's picture
19kitty91 says:

how can you tell if a egg is fertile?
i've got two eggs at the moment which i am incubating... they were given to me by my uncle as he found a free range farm and thought it would be a good present for easter...
but i don't know if they are fertile?
(it's the 2nd day today that i have had them incubating) and don'y know what to do?
please help me with this one.

posted on Tue, 04/10/2007 - 5:02am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Since the eggs have been incubating, you can tell which are fertile and still alive, fertile but with dead embryo, and infertile by candling the eggs. Since it is the first time, I would wait till they eggs have been incubated for 4-5 days.

Hold a light up to the egg (while the room is dark). The light shines through the shell. If the egg is infertile it will be clear inside. If it has an embryo you will be able to see the blood vessels. If the embryo died at an early stage you'll see a ring of blood around the air cell.

See online:
"Candling chicken eggs"
"Candling eggs"
"Candling Pictures by The Easy Chicken"

posted on Tue, 04/10/2007 - 5:48pm
Anonymous's picture
Anonymous says:

How long can an egg be left and still produce a chick? I have a hen at the moment who is sitting on eggs, but someone who fed them yesterday accidentally locked her out of the hutch so she has not been able to lay on them, it wasn't until this morning that i realised she was locked out and i immediatly opened the hutch again so she could get back to her eggs. The eggs had gone quite cold but she sat on them straight away. Can they still hatch? Also since she started getting broody none of the other chickens or her have been laying any more eggs, she's only sat on 2, why is this?
Thanks any reply appretiated.

posted on Sun, 04/15/2007 - 6:18am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

The effect of loss of heat during the incubation of chicken eggs depends on where the embryos are in their development. There are two critical times and if they are chilled during this time malformations and death are common. It takes a while for the egg content to cool off, so a few hours may not be a problem.
Because of hormonal changes - once hen goes broody she stops laying eggs. She also has a reduced appetite. Two adaptions to encourage maximum hatchability.

posted on Thu, 04/26/2007 - 5:04pm
Anonymous's picture
Anonymous says:

We have a hen that just hatch out 5 little chicks,the other eggs haven't hatch yet and we are keeping them warm for a few more days as she will not go back to them. Are we just wasting our time? Another thing we can't candle the eggs because they are a meduim brown and the light won't go through enough to see inside the egg. What do advice do you give on this.

posted on Sun, 04/15/2007 - 11:07pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

It's been a few days since you posted - if they haven't hatched by now, they most likely aren't going to. It can take 24-48 hours for an entire batch of eggs to hatch out.
You should be able to candle brown eggs if you have a strong enough light and the room is dark. At this stage, if they are solid when you candle, there might be a chick in them. If they feel very light - handle with care since they are probably rotten and may explode (very nasty smell).

posted on Thu, 04/26/2007 - 5:24pm
Bay's picture
Bay says:

My Biology professor gave me a fertilized egg to try and hatch. I've been keeping the egg warm, turning it, and keeping it moist. The egg is about 10 days old right now, and I just want to know if there's any way for me to be able to tell if the baby chick inside is still alive.

posted on Tue, 04/17/2007 - 12:17pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

You can candle the egg to see if there is an embryo in it. You should be able to see an embryo by three days of incubation. By seven days you can even see the embryo move. If the embryo dies, you'll get a ring of blood around the air cell at the big end of the egg.
How have you been keeping the egg warm? It has to be incubated at the correct temperature for the embryo to develop correctly.

posted on Thu, 04/26/2007 - 5:26pm
Anonymous's picture
Anonymous says:

can egg yolk be on a legquater that has already been processed and what does a egg yolk look like if so is it safe to eat?

posted on Wed, 04/18/2007 - 9:31am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Not sure what you mean by 'egg yolk on a leg quarter' or what you mean by 'processed'. Egg yolk is typically yellow in color so if it was on chicken meat you would be able to see it. As with all egg products, they are safest when cooked.

posted on Thu, 04/26/2007 - 5:28pm
Wishing for chickens's picture
Wishing for chickens says:

I live in St. Paul. At my previous residence, my neighbor kept chickens. They were a huge neighborhood attraction, with all the neighborhood kids stopping by to check them out each evening.

I would like to try keeping a few chickens myself, but I don't know what the regulations in St. Paul are. Was my neighbor's flock of chickens even legal? If so, is there a limit on the number you can keep, or rules about where you can keep them or what kinds you can keep?

It seems to me that 4H kids involved in the poultry program I've talked to at the State Fair live in the city, so it must be OK under some circumstances...

Any information you can provide will be greatly appreciated.

posted on Wed, 04/18/2007 - 8:34pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

There are some areas of the city that can have chickens - you need to check with your local admin office. For many areas, they don't allow you to keep roosters, because of the noise. There is no way to 'de-crow' a rooster. There are also some areas where you can keep chickens only if your neighbors agree.

posted on Thu, 04/26/2007 - 5:28pm
Anonymous's picture
Anonymous says:

Decrowing roosters is done, but it can be hard to find a vet who knows how or is willing to do it. It is a tricky procedure because birds are very sensitive to anesthetic, and therefore is quite expensive. Some people think it's cruel, but I don't see how it's any crueler than caponizing, and it's certainly more humane than killing it, which is the alternative for many roosters.

posted on Wed, 10/10/2007 - 4:05am
Irwin's picture
Irwin says:

So in the wild what happens to all these unfertilized eggs if nobody is collecting them? It'd be interesting to just stumble on a truly wild colony of chickens and see what happens to all their eggs and how big of a group they'd eventually become if they hatch so quickly. In their natural habitats did chickens just form colonies and hang out in the same area all year round since they couldn't really fly anywhere? This is fascinating stuff!

posted on Wed, 04/18/2007 - 11:44pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Typically, in the wild, birds only lay eggs that they are going to sit on. The only true wild colony of chickens that I know of is the Jungle Fowl in Asia. They are the ancestors of our present day chicken breeds. They only lay 10-12 eggs a year. It is only through genetic selection that we have chickens that lay so many eggs in a year.
It is interesting though, there is a group of chickens living in the Florida Keys that are considered 'feral'.

From a tourist write up on the Keys:

"Our favorite animals in Key West are the feral roosters you see everywhere. You won't have trouble spotting them; the tourist brochures say there are 2,000 "wild" chickens on the island. They roost in the bushes. Mother hens guide tiny chicks across busy streets. They scurry around outdoor cafes."

I don't recall see lots of eggs laying around abandoned in the streets when I was there, so assume that once they went feral they reduced the level of egg production they were capable of. They are also not light controlled, which affects reproduction, so won't lay year round.

posted on Thu, 04/26/2007 - 7:26pm
Lance's picture
Lance says:

How long are hens fertilized after mating with a rooster?

posted on Thu, 04/19/2007 - 5:05pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Hens can lay fertile eggs for several months after they have mated with a rooster, but the percent of eggs laid that will be fertile decreases dramatically after a couple of weeks.

posted on Thu, 04/26/2007 - 3:54pm
Anonymous's picture
Anonymous says:

Dr Jacob, are you certain on this? I thought after 3 weeks, the chicks would all be the offspring of my new improved replacement rooster...
After 3 weeks with a new rooster, what do you suppose the % of chicks are the offspring of that accursed old rooster?

posted on Sat, 06/02/2007 - 4:07pm
Bob H's picture
Bob H says:

I have a flock of Aracanas.
But there is a Plymouth Barred Rock that spends time with them.
I want to get my Aracanas sitting on eggs that are true Aracana.

My question is, how long do I have to seperate the Plymouth Barred Rock to ensure that my Aracana chicks are pure? Or should I say, how long does the sperm stay viable in the hen.

Thanks for any help.

posted on Sun, 04/22/2007 - 12:24pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Hens can lay fertile eggs from a mating for months after a mating, but the likelihood goes down after a few weeks. A few sperm have been known to be viable for several months after a mating, though they are rare.
My best advice is to incubate the eggs - any chicks that hatch with a tail, muffs and a beard are not Araucana chickens. Araucana chickens have no tail (rumpless) and feather tufts. Amercaucana chickens, which result from the cross between an Araucana chicken and a chicken of any other breed, have a rump and instead of tufts have muffs and a beard. So any chicks that hatch are not pure Araucana chicks will be easy to spot.

posted on Thu, 04/26/2007 - 3:56pm
Gary's picture
Gary says:

Why can chicken lay eggs on different days yet hatch at the same time?

posted on Sun, 04/22/2007 - 9:44pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

It is an unique characteristic of birds - the ability to 'hibernate' between being laid and before incubation begins. If heat is removed after incubation starts they loose this ability.

From an article in the Audubon magazine -

"The embryo needs to be heated to at least 77 degrees Fahrenheit to grow and does not grow properly until it is at about 95 degrees Fahrenheit. In most climates that means heat needs to be provided by an adult. Below 25 degrees the embryo is at what's called “physiological zero,” meaning that it is effectively in a state of suspended animation. By not incubating, many birds keep their eggs at physiological zero until most or all have been laid; that allows all the eggs to hatch and the nestlings to fledge at about the same time. Species such as parrotlets and many owls, instead, begin incubating with the first or second egg. As a result, the eggs hatch asynchronously. Ornithologists had an explanation for this behavior: The range of nestling ages spreads out the food demands of the entire clutch, potentially allowing more chicks to survive."

posted on Thu, 04/26/2007 - 7:28pm
Anonymous's picture
Anonymous says:

I have 10 bantam chicken eggs taken from the farm where i work. they are all in an incubator but how do i know if they are fertilized? the hens at work run with at least 6 roosters so there is a good chance they are but can i look for any sign? people have told me to shine a flashlight or float them but i dont know what i'm looking for. Please help me i've really fallen in love with these eggs!! :)

posted on Mon, 04/23/2007 - 4:00pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

The procedure that your friends have told you about, where you shine a light through the egg, is known as candling. You can't tell whether or not an egg is fertilized by candling. You can only tell by breaking them out or incubating them and candling when they have been incubated to around 3-5 days of age. If you check some of the earlier discussions you can find websites with photos showing you what to look for when candling.
The floating of eggs in water is more related to the age of eggs. Eggs have an air cell that is typically located in the large end of the egg. When the egg is fresh, this air cell is small, but as the egg ages the air cell increases in size. When submerged in water, fresh eggs will sink to the bottom and lay flat (because the air cell is small). Older eggs will stand straight up and down (because of the larger air cell) and will float higher in the water as they age. Very old eggs will float to the top. Nutritionally the eggs are the same, regardless of age, they just don't look very nice when you try to fry old eggs (because egg white spreads out in the pan).

posted on Tue, 06/17/2008 - 9:10am
Anonymous's picture
Anonymous says:

How can you tell if the egg holds a female or a male, just by looking at it?

posted on Mon, 04/23/2007 - 8:06pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

You can't tell whether or not an egg is fertile just by looking at it. Nor can you tell if a fertile egg will yield a male or female chick.

As an aside, unlike mammals, it is the female that decides the sex of the offspring. Males are ZZ while females are ZW (compared to males where the male is XY and the female is XX). So manipulation of the sperm will have no effect on the sex of the offspring (as can be down with dairy/beef cattle).

posted on Thu, 04/26/2007 - 5:49pm
Anonymous's picture
Anonymous says:

What are signs of mites on chickens?
Can you see mites?

posted on Sun, 04/29/2007 - 5:25pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

There are different kinds of mites - some you can easily see, others not so.

With a minor infestation of mites you may not notice anything wrong with the birds. With heavy infestation the birds become anemic since mites are blood suckers. For layers, a drop in egg production can occur.

Northern fowl mites are the most common around here. You can see them as fast moving black dots around the vent area of the chicken. In a heavy infestation you may see clumps of eggs around the shafts of the feathers.

For more information on the location and treatment of fowl mites, check out the online publication Common continous external parasites of poultry

Another mite that can effect poultry is Chicken Mite or Red Mite. This external parasite spends most of its life off of the birds and only attaches itself to the bird to feed, typically at night. You may not be able to see the mites on the birds, unless checking at night. The mites typically hide in the crevices in the barn.

For more information and treatment of Chicken Mites, check out the online publication Common intermittent parasites of poultry

posted on Tue, 05/01/2007 - 10:35am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

There are different types of mites - Northern Fowl Mites are the most common. You can usually tell if you have them by seeing black flakes around the vent area (this is the fecal material from the mites). If you look carefully you will see small flecks moving around quickly.

Red mites, however, live in the cracks in the barn and come out to feed on the birds only at night so it is rare to see one on a bird.

For more information on mites see Common continous external parasites of poultry and Common intermittent external parasites of poultry.

posted on Tue, 05/20/2008 - 1:56pm
2manychickens(105)'s picture
2manychickens(105) says:

how long after a hen lays her eggs does it take the rooster to fertilize it

posted on Tue, 05/01/2007 - 10:12am
Liza's picture
Liza says:

Chickens and other birds use internal fertilization. That is, the hen and rooster mate, and then the hen produces eggs. (Hens will lay eggs whether or not they've mated with a rooster, but eggs produced without a rooster are infertile.) Once an egg has been laid, it can't be fertilized. It either already contains an embryo, or it doesn't.

posted on Tue, 05/01/2007 - 10:46am
Molly K.'s picture
Molly K. says:

Thanks to the American Egg Board and this page... I now know that the long ropey strand in each egg are called Chalazae. Had a conversation with my boyfriend about it last night and we knew it wasn't an umbilical cord because the grocery store eggs we consume are not fertilized or connected to the mother like we are. Even though it definitely looks like one. Well thanks!

posted on Tue, 05/01/2007 - 3:03pm
Anonymous's picture
Anonymous says:

hello, i accidently cracked open an egg that i thought was a dud but it wasnt and there was a chick alive in it. what should i do? im scared that it will die, will it die?
but if you could email me asap and gibe me an answer id be so pleased.

posted on Tue, 05/01/2007 - 4:02pm
Liza's picture
Liza says:

I'm not a chicken expert, so I'm hoping that Jacquie will check this thread and respond to you with some expert advice.

My $0.02:
I would think that your chick's survival chances hinge on how close it was to hatching before you cracked the egg. If it would have hatched on its own in a day or two, it probably has a better shot than if it wasn't supposed to hatch for another week or more.
Like all young animals, it probably will have a tough time regulating its temperature, so you'll have to keep it warm without overheating it.
And you'll have to keep it hydrated and fed, but I don't know how you do that.

Sorry to not be more helpful.

posted on Tue, 05/01/2007 - 4:12pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

As Liza indicated, survival will depend on the stage of development at which the egg was cracked, as well as where the egg was cracked.

At about 20 days of incubation an embryo will poke a hole through the inner shell member and place it's beak in the air cell, which has enlarged during incubation. At this time the embryo takes it's first breath and technically becomes a chick. As the chick breaths, carbon dioxide builds up in the air cell and when it reaches the right level the chick is triggered to break out of the shell.
If the crack broken any blood vessels, the embryo could bleed to death, which is the main reason it is not recommended that you help chicks out of the shell.
Before a chick hatches, it absorbs the remaining yolk material, in the yolk sac, into its abdomen. The chick can live of this material for the first couple of days - which is why it is possible to mail day-old chicks through the post. The main concern will be water - you need to show the chicks where the water is - typically dipping their beaks in the water is sufficient.
Chicks are not able to maintain their body temperature for the first few weeks so need to be provided with supplemental heat - usually around 85-90 degrees F.

posted on Fri, 05/04/2007 - 5:35pm
2manychickens(105)'s picture
2manychickens(105) says:

hello anonymous what you will need to do is feed the chick a scrambled egg with no butter or oil or salt or anything in it it sounds wierd but it's true.another thing is I'm totally against antibiotics but you'll need to give it some in it's water to help it stay alive. Put it in a box and put a heat lamp on one side of the box and it will choose what side it want's to go to when it get's to hot or cold keep the heat lamp about 20 inches up from the bottom of the box and your set.Lets just hope you did this early enough. I wish you luck and hope you can keep it alive

posted on Thu, 05/03/2007 - 9:36am
Anonymous's picture
Anonymous says:

How many years can hens continue to lay eggs? And what is the rate of decrease in laying each year? For example, will a white leghorn lay 300 eggs one year, 275 the next, 250, etc? I know this can't be figured exactly, but what would the averages be? I am asking because of a rather odd assignment in a finance class, so it doesn't matter what is "economically viable." I just need to know the "possibilities."

posted on Wed, 05/02/2007 - 8:24pm
2manychickens(105)'s picture
2manychickens(105) says:

Hi anonymous of course you know that you never count on one number so just picture this a full sized chicken lays 300 eggs a year and their first year is the best one and they will lay for ten to twelve years and they do decline in the number of eggs per year. at ten years old they lay about 200 eggs give or take a few. so I hope that answers your question

posted on Thu, 05/03/2007 - 11:38am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Hens are hatched with the total number of ova they will ever have, just as humans are. Males regular produce sperm, but the gametes of the female are fixed at hatch/birth.

Hens can lay for several years - the number of eggs will depend on the management and nutrition of the hens so it is hard to give a significant figure.

The average leghorn lays about 275 eggs in the first year. After a properly managed molt, she will lay about 80% of that rate in the next 6-8 months. You'll get the about the same reduction rate each year.

There are, of course, always exceptions to every rule. My father had leghorn hens that laid at a relatively high rate of production continuously for 2-3 years (without the use of a molting system). Once they stopped laying the were eaten so I'm not sure what they would have done after a rest.

posted on Fri, 05/04/2007 - 5:41pm
vidal gabe's picture
vidal gabe says:

i don't know. probably atleast it decreases 25,maybe. i'm not sure.

posted on Sat, 05/05/2007 - 6:36pm
2manychickens(105)'s picture
2manychickens(105) says:

will two chickens that have never been around mate (a hen and a rooster) each one is about two years old I have 200 chicks and two full grown hens. I borrowed a rooster from a friend I don't know if I'm wasting my time with him

posted on Thu, 05/03/2007 - 9:23am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

While female rabbits can be very picky about their choice of mate, that is not the case with chickens. Typically a rooster will try and mate with any hen available - whether they are 'familiar' with each other or not. The rooster may have to chase the female around for awhile before getting the deed done though.

posted on Fri, 05/04/2007 - 5:43pm
animalfweek's picture
animalfweek says:

does anyone know how to tell if a chick is a rooster or a hen the day they were born

posted on Thu, 05/03/2007 - 12:45pm
2manychickens105's picture

the way to tell is to hold them upside down by thair two long toes and if they try to get up then it is a rooster and if the ends of the wing feathers are streight like someone just trimed them then it is a rooster and if the middle ones are longer thenthe edge ones there a hen.

posted on Thu, 05/03/2007 - 1:07pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

It is difficult to sex chicks at day of hatch. There is a vent sexing system, but it takes a lot of training to be able to have any accuracy. There are different sex-linked crosses that make it possible to separate males and females based on feather color or feather development - but the chicks have to be from a very specific cross.

Check out the online publication 'Methods for sexing day-old chicks'

posted on Fri, 05/04/2007 - 5:48pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

It is difficult to tell a pullet from a cockerel chick when it is first hatched - unless you are trained at vent sexing or the chicks are the result of specific crosses. There are some physical characteristics, like feather color or speed of feather growth, that are linked to the sex chromosomes (Z and W in chickens rather than the X and Y in mammals) and for certain specific crosses you can sex day old chicks on these characteristics.

There are links to four factsheets on sexing day-old chicks from University of Minnesota's poultryu.com website that give more information on these crosses as well as the commercial industry practice of vent sexing.

posted on Wed, 01/30/2008 - 12:02pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

It is very difficult to tell the difference between pullets and cockerels at day of hatch. In industry there are a couple of ways they sex chicks (e.g., females for egg production and separating males and female broilers)

  1. Vent sexing - this is a technique developed by the Koreans. Today it is still used in some hatcheries, but it takes a LOT of training since you are looking for very minor differences;
  2. Sex-linked traits such as feather color or growth of wing feathers.

For more information on sexing day-old chicks, see the factsheets linked to from the U's poultry website.

posted on Mon, 02/11/2008 - 10:32am
Anonymous2d's picture
Anonymous2d says:

If on the seccond day in the incubator you can see something in there is there a possibility that there is really nothing in there?

posted on Mon, 05/07/2007 - 3:00pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Depends on how you are seeing something - I will assume you mean by candling. The embryo is very small at 2 days but you might see if it you now what you are looking for. You may be seeing the chalazae and confusing it for an embryo.

Photos of different stages of embryo development can be see online at a private website

You can also see a movie of a 2-day old embryo's heartbeat.

posted on Mon, 05/14/2007 - 3:08pm
becky's picture
becky says:

I have eight mature hens. When I went out to collect eggs this Sunday, there was an egg in the middle of all the others that is 1 1/4 inch long. It looked pretty much like all the rest of them. Is it common for chickens to lay really small eggs like this, or could something else have gotten in there and laid it?

posted on Mon, 05/07/2007 - 4:13pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

It is unlikely a wild bird came and laid in a nest being used by chickens, but I guess it is always possible.

BUT it is possible for a chicken to lay very small (and very large) eggs. Small eggs can result from one of two things
- 'pullet eggs' which are the eggs that young female chickens lay when they first start laying eggs.
- Sometimes a piece of something can be shed into the oviduct (like a piece of the oviduct itself) and the hen will make an egg around that material. It will turn out to be a very small egg, and yolk-less

posted on Mon, 05/14/2007 - 3:17pm
myster typer's picture
myster typer says:

I did not learn anything i needed to know about chickens. What's up with that?

posted on Tue, 05/08/2007 - 1:45pm
Liza's picture
Liza says:

Wow. I'm kind of surprised to hear that. With all the links now in these posts, and the range of questions that have been asked and answered, it's amazing to me that you didn't find ANYTHING you needed to know about chickens.

So...what DO you need to know about chickens? And if you find your information somewhere else, it would be great if you'd post it back here.

posted on Tue, 05/08/2007 - 2:17pm
Lozz's picture
Lozz says:

i need some help... i have this adorable bantam hen, and i would like 2 breed her but i only have a male isa brown mix rooster who is alot biger than she is.....is it possible 2 breed them? or would the eggs be 2 big for her 2 lay and mite kill her?

posted on Sat, 12/01/2007 - 9:16pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Try the University of Minnesota's www.poultryu.com website - I have links to a wide variety of extension publications, sorted by category.

Hopefully you will find the information you are looking for - or find something you didn't know you needed to know.

posted on Mon, 05/14/2007 - 3:20pm
Rachel Conn's picture
Rachel Conn says:

I got chickens about 13 days ago. For about three days my hens spent some time with a couple of roosters. I've been collecting the eggs. But I found that a hen had been hiding a few eggs in the rabbits house. I collected them and put them in the fridge. but then we talked about letting them hatch. Should I take them out of the fridge and let the hen sit on them? Should I just let her sit on the ones that she lays from now on? How long will they be fertile since there are no more roosters. Will she get mean and make the bunny uncomfortable in his house?

posted on Tue, 05/08/2007 - 3:22pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

The question may be mute if the hen isn't broody - just placing eggs under a hen doesn't make them sit on them.

You can make your own incubator to hatch small amounts of eggs. The instructions are available online.

If they have only been in the eggs a couple of days you might get them to hatch. More than a few days at the lower temperature of the fridge will reduce the hatchability the longer they are stored there.

If the hen has not been with a rooster for 10 days, the percentage of fertile eggs will decrease dramatically so having them sit on eggs now may be futile.

Rabbits and chickens usually get along - again, it depends on the temperament of the individual birds.

posted on Mon, 05/14/2007 - 3:27pm
becky's picture
becky says:

hi i was wondering if i got a chicken egg from a farm is there any chance of me being able to hatch it without an incubatorand if so how?

posted on Fri, 05/11/2007 - 4:54pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

It is very hard to hatch a chick without an incubator. There are old techniques that were used before electricity and incubators were invented, but most are not practical.

I have heard of people having success using a light bulb to supply the heat necessary to hatch eggs, but you have to watch the temperature very carefully and sprinkle with water occassonally.

posted on Mon, 05/14/2007 - 3:37pm
boo's picture
boo says:

can you hatch chcken eggs without a incubator?

posted on Fri, 05/11/2007 - 4:56pm
amz's picture
amz says:

can you help me look after my chick,
i have a egg at the monment but how do i look after it.
and can you tell me what they eat,how you clean it and what other stuff you know.
thanks

posted on Sat, 05/12/2007 - 11:16am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

If I understand your question, you have an egg you want to hatch to a chick - and then want to know how to care for it. Is that correct?

You need to make sure your egg is fertile or it won't hatch - where did you get your egg? If it is from the grocery store, it is infertlie and won't hatch. If it is from a farmer that you know has roosters with his hens, the chances are it is fertile.

If you don't have an incubator, you can make one. There are plans available online.

For a single egg, if you don't have an incbutor, you can try using a light bulb - but you need to watch the temperature (should be about 99 degrees F).

Once the chick hatches, you need to supply it with warmth (a light bulb will work) since they are unable to maintain their own body temperature for the first 4-5 weeks after hatching. You can use shavings as a bedding material. Newspaper is not a good bedding material. Replace the shavings if they get dirty or wet. The smell is a good indication of the quality of the bedding.

You need to get chick feed and the chick needs feed and water from the second day of hatch.

posted on Mon, 05/14/2007 - 3:43pm
heather's picture
heather says:

I have a hen on fertile eggs right now --she has been sitting on her eggs for almost 3 weeks now. Every day I find eggs missing. I think she is eating her chicks. I would like to take the 2 remaining ones in and try to hatch them myself, as it shoudl be any day now. Are there any tips you can give me to get these hatched without an incubator, for the remaining few days till they hatch?
Thank you.

posted on Mon, 07/09/2007 - 9:37pm
Amie's picture
Amie says:

hiya can you help me look after my chick thank you

posted on Sat, 05/12/2007 - 11:17am
dewgirl21's picture
dewgirl21 says:

What a great page of information! I recently started getting farm-fresh eggs from my neighbor, and have a couple questions I don't think I read anywhere! 1)She indicates that she collects the eggs daily and cleans them @ some point, AND i assume, refrigerates them...what would cause me to get a 'bad egg' - they are def fertilized, and as I'm getting used to 'finding' something like blood spots, I almost gave up getting these eggs when 'something' was def in the egg other than yolk when i broke it open...but didn't investigate as i was just getting my breakfast - so i guess the question is - how could this be....did she perhaps not truly collect it soon enough and a chick was growing? secondly - she has a variety of colored eggs, mostly white, but some brown and an occasional green one that is very cute...do these come from different types of chickens? Thanks for this great website and it's contributors!

posted on Mon, 05/14/2007 - 5:23am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Some strains brown egg layers have a higher incidence of blood spot eggs. A deficiency of Vitamin K (required for blood clotting) can increase the frequency even more.

So - how does a blood spot egg come about? The ovaries of chickens are highly vascularized. When an ova (genetic material on the yolk) is released (ovulation) occasionally a small blood vessel will be damaged and you'll get some blood on the yolk. Occasionally a piece of the wall of the oviduct will shed while the egg is being assembled, and it gets incorporated into the egg.

If the farmer supplying the eggs is getting a lot of blood/meat spot eggs you should suggest that she/hen candle the eggs before selling them.

Different breeds of chickens will lay different colored shelled eggs. For most breeds, you can tell what color egg they lay by looking at the ear lobe color - there is a correlation between egg color and ear lobe color. Breeds with white earlobes, regardless of feather color, typically lay white eggs. Breeds with red earlobes, again regardless of feather color, typically lay brown eggs.

The Araucana is a breed of chicken from South America. A true Araucana has no tail and lays green shelled eggs. If you cross an Araucana chicken with any other breed, the egg color gene is dominant so you get an Ameraucana breed that has a tail and lays green, blue, or light pink. Thus they are sometimes referred to as the 'Easter egg chicken.'

Check out the Ameraucana breeders Club website for more information on Ameraucana chickens.

posted on Mon, 05/14/2007 - 3:55pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Some brown egg laying breeds are more prone to having blood spots. A deficency in vitamin K (important in blood clotting) can also increase the incidence of blood spots.

Blood spots can happen as the result of two problems:
1. The ovaries are highly vascularized (lots of blood vessels) and sometimes of the blood vessels gets damaged during ovulation (release of the yolk) and bleeding occurs. It is usually only a little bit of blood that ends up on the yolk surface.
2. Sometimes you get some bleeding as the egg is being assembled in the oviduct. The blood then appears in the egg white.

If you buy your eggs from the store you shouldn't see blood spots since the eggs are candled to remove any such eggs before they are packaged for sale.
"Nest-run eggs" are not candled - like the ones you are getting from your neighbor. Then you are taking a chance, especially for brown eggs. I would recommend breaking the egg in a dish before adding it to any ingredients - then if there is a blood spot only the egg needs to get thrown out and not all the rest of the ingredients.
If you are getting a lot of them from your neighbor you might suggest she candle her eggs to remove blood spots, or check her diets for vitamin levels.

Different breeds of chickens lay different colored egg shells. For most breeds you can tell what color shell the hen of a breed will lay by looking at her ear lobe color since there is a correlation between ear lobe color and egg shell color. Typically, if the breed has white ear lobes, the hens will lay white shelled eggs. If the breed has red ear lobes, the hens will lay brown shelled eggs.

Then there are the green eggs - The Araucana is a South American breed that is tail-less and the hens lay green shelled eggs. If you cross an Araucana with any other breed, you get an Ameraucana. The egg shell color is genetically dominant and the tail-less character isn't - so Ameraucanas have a tail and lay green, light blue or light pink eggs. They are often referred to as the Easter Egg Chicken.

For more info on the Ameraucana breed - check out the Ameraucana Breeders Club website.

posted on Mon, 05/14/2007 - 5:04pm
Michelle's picture
Michelle says:

Dr. Jacquie Jacob, I love reading your posts, you have been very helpful in answering many of my questions. But in this one instance, I have to disagree. I'm sure it's just a typo, though I'll detail my protest for the sake of other readers. You state "If you cross an Araucana with any other breed, you get an Ameraucana." which is untrue. Both the Araucana and Ameraucana are distinctly separate breeds recognised by the APA. Perhaps you meant to say that "...you get an easter-egger" (mutt), or "...you get an americana" which is a misspelling most big hatcheries use when selling Ameracauna/Araucana crosses as a real breed. I would also like to direct readers to the Araucana Club of America website for more information on Araucanas.

posted on Mon, 07/30/2007 - 6:23pm
shaun's picture
shaun says:

hi, i was just wondering if you can keep fertilzed chicken eggs in the airing cupboard, and if they will be alright, thanks.
you can e-mail me and tell me if you want sewan16@hotmail.co.uk
add me

posted on Mon, 05/14/2007 - 7:55am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Depends on the temperature and humidity of the cupboard.

Refer to the Mississippi State University publication on the Care and Incubation of Hatching Eggs.

Ideal storage conditions include a 55 degree F. temperature and 75% relative humidity. Store the eggs with the small end pointed downward

posted on Mon, 05/14/2007 - 5:08pm
Rachel Conn's picture
Rachel Conn says:

We have nine egg laying chickens, how much chicken feed should we be feeding them and how many times a day?

posted on Tue, 05/15/2007 - 12:55pm
2manychickens213's picture
2manychickens213 says:

you just need to keep food in front of them all the time

posted on Mon, 05/21/2007 - 1:24pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

2manychickens213 is correct - it is best to provide feed ad libitum, which just means having feed in front of them at all time.

Make sure it is the right feed - layer feeds have higher calcium content than general poultry diets.

If you want to know how much feed they will eat (to help budget purchases of feed) - it depends on the breed of chickens. Small body-type chickens, such as leghorns, will eat more than larger body-type chickens (such as Barred Rocks, New Hampshires, etc.).

Temperature will also effect feed consumption - lower when it is hot and higher when it is cold.

A good online reference is an American Pastured Poultry Producers Association article - Environment Stresses on Laying Hens

posted on Tue, 05/22/2007 - 12:05pm
2manychickens213's picture
2manychickens213 says:

what does it mean when a baby chicken about 3 week old starts losing some of its fuzzy feathers I have 213 chickens and they could be pecking at it but i don't think so cause there is no blood or anything any answer would be great thanks in advance

posted on Thu, 05/17/2007 - 2:31pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Depends on the type of chicken - for most they start losing their down feathers at 3 weeks, and start developing feathers instead. For broiler chickens I have seen many lose their down and have a delay in getting feathers, or get only a few feathers, so they look pretty roughed up. They are putting their feed into growing instead of feathers. Since the buildings are normally heated, it is usually not a problem.

If your chickens are not broilers (meat chickens) and don't get their feathers soon, check their diets - might be low in the amino acid methionine, which is important for feather growth.

posted on Tue, 05/22/2007 - 12:24pm
Anonymous's picture
Anonymous says:

this is a cool egg

posted on Sun, 05/20/2007 - 3:31pm
Patty's picture
Patty says:

How do you tell when an egg is old. I've heard the bigger the air pocket in the shell the older the egg is. Is this true.?

posted on Sun, 05/20/2007 - 6:20pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

You are correct - the older the egg the larger the air cell. You can determin tthe size of the air cell by shining a light through it while you are in the dark (the interior content of the egg lights up). The air cell is typically in the large end of the egg.

A quick and easy way to tell which eggs are oldest, is to place them in water - fresh eggs, which have small air cells, sink to the bottom and lay flat; older eggs start to stand upright and then float a little; very old eggs, which have a large air cell, float to the top.

posted on Tue, 05/22/2007 - 12:15pm
Anonymous's picture
Anonymous says:

Hello, my niece is doing a science experiment by hatching chicken eggs. They are supposed to hatch 5-24-07. My sister says you can no longer see them when candling because they are too big, but the last time they could see them the chicks were moving inside the eggs. Anyway, my sister checked the eggs Sunday morning and they were fine, but when she checked on them a few hours later the incubator light had burned out. She immediately changed the bulb but the temp. had dropped to 72 Degrees F. She is very upset and says that they won't hatch now. Is this true? Is there still a chance for the little guys?

posted on Mon, 05/21/2007 - 8:45am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

They still have a chance - a pretty good chance in fact. Although the temperatu4re in the incubator was reduced, it takes a while for the interior egg temperature to drop. Plus, chicken embryos are pretty resilient at this age. They should start pipping tomorrow - although the cooler period might delay that a couple of hours.

I have heard stories of chicks hatching in the fridge. I'm sure you wondering why someone would put incubated eggs in the fridge - It is common in hatcheries to break open unhatched eggs when chicks are removed from the incbutor, so they can evaluate why they didn't hatch (infertile, dead embryos, etc.). When they can't get to the analysis right away, they sometimes put the eggs in a cooler (so they don't start to stink) - and late hatching chicks have made an appearance during this time.

Let us know how it goes.

posted on Tue, 05/22/2007 - 12:20pm
Anonymous's picture
Anonymous says:

Does anyone know how to sex a Silkie Chick? I have a bunch of Silkies that range from 1 Day old to 4 months and I cant tell the difference. They do not have feathers like regular chickens. I thought maybe by the comb, however some of the females have little combs.

posted on Wed, 05/23/2007 - 1:35pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

It is very difficult to sex day old chicks of any breed. See the University of Florida factsheet, Methods for sexing day-old chicks

Even adult silkies can be hard to sex because they typically have the same coloring, depending on the variety. If they are non-bearded varieties, the size of the wattles that hang from the neck can be used. For bearded varieties the wattles can be harder to see since they are hidden by the feathers of the beard.

The main difference between the two sexes is the feather structure - especially in the tail and back feathers. Males have saddle feathers and females don't.

The American Bantam Silkies Club has lots of information on silkie chickens, including an article on sexing silkies.

"Here are a few suggestions for trying to figure out who is what.

  • The Comb: Usually, a male will have a larger comb than a female. Also, a Silkie cockerel's comb seems to develop faster than a Silkie pullet's comb. However, some males will have very small combs and some females will have very large ones!;
  • The Crest: A Silkie cockerel's crest will be shaped differently that the Silkie pullet's crest. The male's crest should show "little streamers" coming from the back of the crest. It looks a bit "swept back." and not really round. The pullet's crest should be nicely round in shape without the tell-tale streamers.
  • The Wattles: Generally, a Silkie male will have larger and rounder wattles than a Silkie female. However, this trait is a bit easier to use for sexing with non-bearded Silkies. With top quality bearded Silkies, the wattles of both genders are nearly non-existent and even the males frequently show very small wattles.
  • The Spurs: Silkie cockerels will usually have them and the females usually won't.
  • The Feathers: Silkie cockerels will develop "male feathers" on their hackles and saddles. (For those folks in doubt about terminology, the hackle feathers are the ones on the neck and the saddle feathers are the ones just in front of the tail.) These male hackle and saddle feathers are longer and more pointed at the tips than the feathers on the Silkie pullet's hackle or her feathers in front of her tail. On Silkie cockerels, these saddle feathers may even tend to lay over the wings a bit.
  • The Tail: Silkie females typically have rounder and softer tails than the males. Silkie males usually show a more pointed tail because of the presence of "normal" or "hard" feathers in their tails. Keep in mind, however, that although the Standard allows some "hard" feathers in the Silkie cockerel's tail, in top show quality males, hard feathering in the tail is discouraged and often is not present. In creating a perfect "show" Silkies, the ideal for both male and female is a perfectly round and wide tail so this trait may not be as helpful in sexing Silkies as some others."
posted on Thu, 05/24/2007 - 11:49am
Anonymous's picture
Anonymous says:

hey, i have a question. If the airsack in a goose egg gets busted... that means it wont hatch right? cuz some of my eggs had the arisacks broken, but we put them in the incubator anyway, and they havent started to smell and its been 4 days.. what should i do???

posted on Wed, 05/23/2007 - 5:55pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

It is unlikely that the goslings will be able to hatch properly without an intact air cell in the correct location in the egg. The developing embryo has to be in a certain position to hatch properly. Prior to pipping thru the shell their beaks break into the air cell. This is when the embryo starts to breath and is technically now a gosling. As CO2 builds up in the air cell the gosling is stimulated to break out of the shell and starts pipping.

The eggs won't really start to smell unless they go rotten, which requires bacterial contamination. If the shell is intact, at the end of the incubation period you just end up with an egg with a very watery yolk and albumen since their structure has been adversely affected by the heat.

posted on Thu, 05/24/2007 - 11:53am
Anonymous's picture
Anonymous says:

Does anyone know if the temperature in the incubator determines the sex of a chicken? Last spring we incubated some eggs and ended up with a bunch of roosters. We turned the temperature down to about 99 degrees and ended up with mostly hens and a few roosters. Please help as we have already hatched out over 60 eggs and don't want a bunch of roosters this time.

posted on Thu, 05/24/2007 - 12:43am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

The effect of temperature on sex is related to reptile eggs (such as alligators) and not for birds.

The sex of a bird is determined genetically and is set before the egg is even laid. Unlike mammals, however, it is the female that determines the sex of the offspring and not the male.

In mammals, the male is heterozygous (XY) and the female homozygous (XX) so that the male determines the sex of the offspring (i.e., whether or not the sperm has an X or Y gene). Semen 'manipulation' can be used for mammalian food animals to select for particular genders - e.g., producing only male calves for beef production or producing only female calves for dairy production.

In birds, the female is heterozygous (ZW) and the male is homozygous (ZZ) so that the female determines the sex of the offspring (i.e., whether or not the ova has a Z or W gene). In avian species, therefore, semen manipulation is not effective in selecting the sex of the offspring. No treatment of laying hens has been found to affect the gender of the offspring.

While the sex of the chick is determined before the egg is laid, they have shown that male and female embryos may differ in their sensitivity to suboptimal conditions during embryonic development. As a result, the ratio of males and females that hatch can vary depending on incubation condition. Similarly, the ratio of males and females that don't hatch is also affected.

posted on Thu, 05/24/2007 - 12:07pm
Anonymous's picture
Anonymous says:

does this mean they have no chance of hatching at all?? ive placed the eggs so the small end is down and the large end is up... and i still see veins.... but im not sure what this means... the veins look like their attached the the shell rather than the embryo... are they completely toast???

posted on Sun, 05/27/2007 - 6:06pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

I assume this is replying to a previous posting, but I'm afraid I can't find the posting with the specific details.

"Does this mean they have no chance of hatching at all?" - I need to know what you are refering to to reply.

Eggs in the incubator are placed at a 45 degree angle and are rotated back and forth 90 degrees several times per day. If you don't have a 'turner' that does this automatically (which is the case for many eggs hatched in classrooms) they are placed on their side with an egg on one side - you need to add arrows so you know which way to turn the eggs so they go back and forth (you don't want to keep having them go in circles). This mimics what the hen does in nature - she moves the eggs around daily. It prevents the embryo from sticking to the shell which can lead to deformed chicks, if they hatch.

How old are the eggs you are candling, to see the veins? The embryo develops blood veins quite early in its development so it can move nutrients and waste around. It can appear like they are on the inside of the shell, but they are circling the yolk.

posted on Wed, 05/30/2007 - 1:46pm
Anonymous's picture
Anonymous says:

ok... this is a reply to my earlieat post. i asked about my eggs.. the airsacks broke and u explained that they most likely wont hatch... but then i replied that i had the small end down like so where the airsack was is in the same position. i had put them back in the incubator, its been like, 6 days, and they dont smell, and when candled they look like they have veins on the shell rather than the yolk, and i wanted to know if they were dead, and what i should do. Let me know Thanks! ^_^

posted on Thu, 05/31/2007 - 5:14pm
London Dude's picture
London Dude says:

Cheers dude. I was having an argument with my mate the other day about this. Shamfully I was convinced eggs were unborn chickens. I'll just tell him I was being ironic. Good work!

posted on Fri, 05/25/2007 - 10:17am
Worried =['s picture
Worried =[ says:

Help!
My mum is raising some chicken eggs to be hatched and shown for Pre-school children. All of the eggs started late and one hatched last night and It's still not dry this morning! It has a solid feel to it and the yolk sac is outside the body. Will it survive?

posted on Mon, 05/28/2007 - 4:54am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

If the chick hatched with the yolk sac outside of the body, chances of survival are very slim.

Hatched chicks are typically dry within a few hours of being hatched, assuming the hatcher is at the right temperature.

posted on Wed, 05/30/2007 - 1:48pm
Anonymous's picture
Anonymous says:

What will make the yolk of an egg have a green or black color? I have heard certain plants can cause this. Do you know which plants?

posted on Mon, 05/28/2007 - 12:30pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Feeding cottonseed (as seeds or as a meal) can adversely effect the color of the yolk.

Acorns can also cause olive colored yolks.

Canola/rapeseed can be a problem for some brown egg layers (a genetic makeup that makes them unable to handle some of the compounds present in canola).

Eggs can also get a tinge of green if over cooked. The color change is due to the iron of the yolk reacting with the sulfure of the eggs white to form ferrous sulfide. The eggs are okay to eat - though they look bad. Overcooking is defined as boiling the eggs for 10 minutes are longer.

posted on Wed, 05/30/2007 - 2:04pm
kelley's picture
kelley says:

I was wondering how long eggs are good to eat after being gathered maybe I could start dating my cartons and also does not refrigerating the eggs for a week or so effect the edibility of the eggs, perhaps I could get info on the best way to prepare and store eggs also. Thanks

posted on Tue, 05/29/2007 - 12:57pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

When properly stored in the fridge, eggs can be kept for several weeks with no problems. As the age, however, the egg white thins out so they are hard to fry and when hard boiled the yolk doesn't sit in the center of the egg.

The American Egg Board has information on handling eggs as well as several recipes to chose from.

posted on Wed, 05/30/2007 - 2:08pm
Anonymous's picture
Anonymous says:

I have a mallard hen that has a nest of 14 eggs that iam pretty sure are fartilized. The ducks usually only 8-13 eggs. She won,t sit on the nest. What should I do? My parents don,t want any more ducks unless it is natural. Do i have to more the drake away? Is there any thing I can do?

posted on Thu, 05/31/2007 - 6:27pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

You can not make a hen (chicken or duck) to go broody. The desire to sit on eggs (to brood) is hormonal. Hens will normally go broody in the spring, when days are increasing.

It is possible to hatch duck eggs using a broody chicken hen. If you can find a broody hen then you can hatch the duck eggs naturally.

Those are really your only two options.

posted on Tue, 06/05/2007 - 9:58am
anthony's picture
anthony says:

hi thanks for your info. i have not eaten eggs for a whole year because my partners dad put me off by telling me that the white stringy stuff in eggs was chicken sperm. now i can go back to enjoying my egg sandwiches with out the thought of eating chicken sperm!! thanks again!

posted on Thu, 05/31/2007 - 7:04pm
Anonymous's picture
Anonymous says:

I have a chicken question. Can Bantam roosters reproduce with standard size hens? We know he is trying, but I'm wondering if the eggs will be fertilized?

posted on Sat, 06/02/2007 - 1:07pm
Colby's picture
Colby says:

Yes it is possible i know from experience.

posted on Sun, 06/03/2007 - 8:29pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

It is technically possible for a bantam rooster to mate with a standard hen - but if the difference in size is too great it is unlikely he is succesfully mating. To mate, the rooster gets on top of the hen, holds it by the back of the neck and then their cloacas (located at the rear ends) come in close contact to transfer seminal fluid (with sperm) to the hen.

posted on Tue, 06/05/2007 - 10:00am
Colby's picture
Colby says:

I have chickens that are about three months old, how do I tell which are hens and which are roosters?

posted on Sat, 06/02/2007 - 1:58pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Sexing of chickens depends on the type of chickens. At twelve weeks of age the chickens are not yet sexually mature so the differences are subtle. Roosters typically have a larger comb than females. The tail feathers are also different between the two genders. Although they are not sexually mature, cockerels will start strutting and fighting with other males.

For some chicken breeds, there are differences in color patterns between males and females (not the case if they are white chickens, of course, since all are white).

posted on Tue, 06/05/2007 - 10:05am
Anonymous's picture
Anonymous says:

well how does a chicken have a baby?

posted on Tue, 06/05/2007 - 12:34pm
Anonymous's picture
Anonymous says:

my malard started sitting on her nest yesterday. only 25-29 days left till they hatch. i know this is the chicken and the egg not duck and the egg. i'm sorry , but this was the best site i found. i know you are all probably all chicken fans but does anyone maybe want to have baby mallard?

posted on Sun, 06/03/2007 - 6:29pm
Colby's picture
Colby says:

I have raised some mallards what do you need to know?

posted on Mon, 06/11/2007 - 8:28pm
Colby's picture
Colby says:

What came first the chicken or the egg?

posted on Sun, 06/03/2007 - 8:40pm
mexi's picture
mexi says:

well since god created 2 animals at a time when he made the world the chiken was first!!!!!!!!!!!

posted on Mon, 06/04/2007 - 2:29pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

This is a philosophical question - and the answer depends on whether you are an evolutionist or a creationist.

For the creationist, the chicken came first

For the evolutionist, the egg came first.

From the How Stuff Works website:

In nature, living things evolve through changes in their DNA. In an animal like a chicken, DNA from a male sperm cell and a female ovum meet and combine to form a zygote -- the first cell of a new baby chicken. This first cell divides innumerable times to form all of the cells of the complete animal. In any animal, every cell contains exactly the same DNA, and that DNA comes from the zygote.

Chickens evolved from non-chickens through small changes caused by the mixing of male and female DNA or by mutations to the DNA that produced the zygote. These changes and mutations only have an effect at the point where a new zygote is created. That is, two non-chickens mated and the DNA in their new zygote contained the mutation(s) that produced the first true chicken. That one zygote cell divided to produce the first true chicken.

Prior to that first true chicken zygote, there were only non-chickens. The zygote cell is the only place where DNA mutations could produce a new animal, and the zygote cell is housed in the chicken's egg. So, the egg must have come first.

posted on Tue, 06/05/2007 - 10:11am
Rachel Conn's picture
Rachel Conn says:

I have one chicken that lays these really huge eggs that have little cracks in the shell, the shell isnt cracked really it just has crackled lines around the middle I think because its so huge and some times a chicken will lay an egg with some blood on the shell. I'm woundering if these eggs are hurting the chickens. Does the type of food or volume of food effect the size of the eggs?

posted on Mon, 06/04/2007 - 11:24am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Several things effect egg size. Diet is definitely one factor, but mostly adversely (i.e., if the diet is inadequate they will lay smaller eggs).

Another factor is age of the chickens:
- Hens lay larger eggs as they age. As hens get older, they sometimes release two yolks, resutling in larger, double yolk eggs.
- When pullets first start laying eggs, they occasionally lay double yolk eggs.

The blood on the shell is because it was hard for the hen to lay the egg and has caused a bit of damage to the vagina (part of the oviduct that adds the 'bloom' and holds the egg till it is laid) and they bled a bit.

The little cracks that you are seeing around the middle of egg are said to have 'body checks'. These are formed when the eggs shell is cracked while it is still in the shell gland and additional shell is laid to down to 'fix' the crack. There can be an increase in the incidence of body checks if the hens are being improperly handled or if are frequently reacting to something that has startled them.

posted on Tue, 06/05/2007 - 10:23am
Anonymous's picture
Anonymous says:

I have four hens and a rooster. One of the hens this a.m. was lolling around on the ground in the yard. My husband went out to check and she died right in front of him. She had blood on her bottom and looked as though she was 'inside out' so to speak. She had bben fine. About an hour later the other hens and the rooster were fighting over something in the yard and I went out to see the fuss. It was a dead baby chick. It seems as though the hen had a live chick inside her. I cannot find anything about this. I am convinced that is what killed her. They lay regularly, once/day and lately we have only been getting three instead of the four and were wondering why. So sad. Is this rare?

posted on Tue, 06/05/2007 - 8:14am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

I have never heard of a chick hatching inside a hen and I doubt that is what happen. It is probably just a coincidence. There was probably a hen sitting on eggs somewhere that you couldn't find.

It sounds like the hen had a prolapse - where the insides come out.

See Common laying hen disorders: Prolapse in laying hens online.

Chickens can lay a lot of eggs, but it is rare for a hen to lay an egg every day for an indefinite period of time. They typically lay a 'clutch' of eggs and then miss a day. The size of the clutch varies with breed and age of the hen.

posted on Tue, 06/05/2007 - 10:32am
Anonymous's picture
Anonymous says:

Is it possible for a chicken egg to hatch inside the hen? I think this happened to my hen and she died this a.m. We found the baby on the ground near her body. The backside of the hen had an 'inside out' look to it.

posted on Tue, 06/05/2007 - 8:34am
Anonymous's picture
Anonymous says:

Thank You. Also, sorry for the double posting on this. I didn't realize my first question was posted. The hens are young, 5 months or so and have been laying for about a month. The link was helpful.

We also have 10 hens that 1 month. How old should they be before laying?

posted on Thu, 06/07/2007 - 9:09am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

The age at which chickens start to lay is breed and strain specific.

Strain-specificity is more for the different commercial strains of leghorns. Some of the strains start laying eggs around 16 weeks, though 18-20 is more typical.

I assume you have something other than a commercial strain of leghorns. Again there are breed differences, but 20 weeks of age is typical. BUT chickens typically have to be 'light stimulated' to start laying eggs (or producing sperm for the roosters). Birds are brought into sexual maturity by increasing day lenghts (i.e., the number of hours of light per day) and typically go out of production with decreasing day lengths. So it is a combination of age, body weight and environment that will effect when a hen starts to lay.

The online factsheet from the University of California, Davis may be helpful: Lighting programs for table egg producers

There are also three online versions of factsheets answering the question, Why have my hens stopped laying?

Anonymous's picture
Anonymous says:

I have two hens that made a nest together and both are trying to sit on the nestat the same time and its not working out so well. should i separate the eggs and make 2 nests or should i just use an incubater? what should i do?

posted on Fri, 06/08/2007 - 10:44pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

It is very common for hens to share a nest when just laying eggs. It is less common to share a nest when they are broody since they tend to be more territorial and eggs can get damaged in the battle for dominance. They both have the preference for the same characteristics of nest, whatever the case may be. I would try mimicing that with a new nest and separate the eggs (assuming they are fertile - if they have been sitting for a few days you can candle them to make sure there are actually embryos inside). I would make the moving in the evening hours. If you have an incubator, that is also an option. Either would probalby work.

posted on Mon, 06/11/2007 - 11:15am
Rusty's picture
Rusty says:

Found some duck eggs 10 days ago that I figured were about a week old. That would make them about 18 days. They were in our irrigation water. We decided to try and see if they would hatch. I've candled them and it's hard to tell since I'm inexperienced. They do feel heavier but some of them are starting to smell. Any ideas. Should I just wait and see if they hatch out? Thanks.

posted on Wed, 06/13/2007 - 10:37am
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

If you found the eggs in the water it is most likely that the embryos are dead. They need air to breath (air goes in and out through the many pores of the shell) and if they are immersed in water they will suffocate. The fact they are starting to smell is also a clue that they are not developing normally.

posted on Thu, 06/14/2007 - 4:48pm
Anonymous's picture
Anonymous says:

my chicken was with a rooster, the next day she layed an egg. we now have three she is sitting on. will the egg be fertilized after being with him just the day before she layed it. i tried to find out on the internet. all i know is the eggs can be fertile up to 3 or 4 days after she is with a rooster. the question is will the eggs she lays be fertile the day after being with a rooster?

posted on Sun, 06/17/2007 - 1:18pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

It takes 24-26 hours for a hen to 'assemble' an egg. If it is going to be fertilized, it has to be done first thing along the assembly line (before the egg white, shell membranes and shell are put down). So it is unlikely that an egg laid within 24 hours of a hen being with a rooster will be fertile - since there is such a narrow window of opportunity. 48 hours later is more likely.

posted on Sun, 06/17/2007 - 9:33pm
Anonymous's picture
Anonymous says:

my hen has been laying normal eggs. this morning i went to collect the egg, but this time it was different. it was underdeveloped. when i picked it up it was like holding a jello egg, really soft, and bright in color. what caused this to happen?
also i was wondering if it is possible for a japanese silky and a large rooster to create any chicks. the japanese silkys are so small compared to the rooster. if he does fertelize the eggs will the baby chicks survive with the egg being so much smaller than a chicken that would normally breed with a rooster of his size. He isnt huge, but probably 3 times bigger than the hens he is breeding with.

posted on Wed, 06/27/2007 - 11:29pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

The soft shelled egg is nothing to worry about - unless it happens every day. Basically it is a premature laying of the egg (before the hen had time to put the shell down). This can be the result of stress or fright.

The main problem with large differences in size between the hen and rooster is the difficulty in matings. As I'm sure you've seen before, a rooster mounts a female, holds her by the back of the head and then their cloacas meet and sperm is transferred. This is very difficult if the rooster is much smaller than the female. In your case, where the hen is much smaller than the rooster, breeding is more likely, but still difficult. If the eggs were fertilzed there is a chance they may hatch depending on the genetics related to size. The embryo would probably be able to develop but be smaller than the genetics would allow it to be - and then it would make up the difference during the early post-hatch period.

If you do get any chicks to hatch, let us know how it went. It is an interesting topic for discussion.

posted on Sat, 06/30/2007 - 2:36pm
jbcricket's picture
jbcricket says:

i was wondering can a chick hatch before 21 days? How long after 21 days can a chick hatch?

posted on Wed, 07/04/2007 - 7:07pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Depending on the temperature of the incubator, a chick can hatch a few hours early. It all depends on when you start counting your 'days'. The temperature can also result in eggs hatching late, but usually within 24 hours of expected hatching time.

posted on Thu, 07/12/2007 - 6:57pm
Anonymous's picture
Anonymous says:

Hi there,
Can you tell me how a hen knows if the egg is fertilized or not? It seems as though I could reach under and pull out an egg without any issue; however, if that egg has been fertilized that hen will peck at me and become very agitated. Any ideas?

Many Thanks!

posted on Thu, 07/05/2007 - 12:46pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

It is typically accepted that the chicken doesn't know if an egg is fertilized or not, at least not in the early stages. I have seen hens sit on golf balls - when the hormones kick in they can become broody with or without eggs.

Having said that, if the eggs are fertile and later in development they are believed to communicate with each other and the hen may pick up on that. Research has shown that if you set two eggs and day apart, they will generally hatch at the same time - somehow the 'communication' of the earlier chick speeds up development of the last egg set. It is an under-researched area.

posted on Thu, 07/12/2007 - 7:00pm
Anonymous's picture
Anonymous says:

Hi, I was wondering, I have 11 hens and one rooster, I read your blog, but am still unsure. My rooster is mating with the hens but they are only 16 weeks old. Will they start laying soon? Do they still have to be 18-22 weeks old to start laying? The rooster has been quite active fot 2 weeks. I thought I read they will start laying 7-10 days after copulation???

posted on Sun, 07/08/2007 - 6:19pm
Jacquie Jacob's picture

Dr. Jacquie Jacob
University of Minnesota - Poultry specialist

Two main factors effect when a hen will start lay - age at sexual maturity and changes in amount of light each day.

The age for sexual maturity will vary depending on the breed of chicken. Some of the highly selected egg laying strains reach sexual maturity as early as 16 weeks. For most breeds anywhere from 18-22 weeks is normal. Copulation does not initiate egg laying - that is really only a factor in species such as cats and rabbits.

The second factor is the number of hours of light per day. As a rule of thumb (and there are always exceptions), hens typically come into lay when day length is increasing and go out of production when day length is decreasing.

posted on Thu, 07/12/2007 - 7:04pm
Anonymous's picture
Anonymous says:

Thank-you, you answered all my questions, being a novice at this your web site is such an asset....Thank you, thankyou.........

posted on Sun, 07/15/2007 - 3:54pm

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