Anatomy of a chicken egg: Everything you need to know

Keeping chickens in a coop in your backyard is a wonderful way to get fresh eggs every day. Since you feed and keep the chickens you can be 100% certain that they have been fed natural, chemical-free feed. Plus, they say happy chickens lay better eggs, and chickens raised in a home coop are usually very happy and content.

If you’re thinking about getting some chickens you probably have a lot of questions about chicken egg anatomy. I surely had. In this article, I will show the answers I found.


How come chickens lay so many eggs?

Chickens are a very interesting species of bird that has been domesticated by humans for thousands of years. The reason we domesticated them is that female chickens, called hens, will produce eggs even if there is no male chicken or rooster around to fertilize them.

Plus, without the rooster, those eggs won’t grow into baby chicks, making them an almost perfect food for humans.

A chicken lays so many eggs because she is “programmed” in her DNA to lay around 10-12 eggs before nesting on them. If the eggs are removed by you or automatic rolls away in the nesting box she will go on “thinking” she needs more before she gets to 10 or 12.

Hence laying a new egg almost every day never reaching 10.

Humans realized this aeons ago and started separating hens from roosters for this very reason. A mature hen will lay 1 egg a day if a rooster is around and do that for approximately 10 days. After that, she will sit on the fertilized eggs until they hatch into baby chicks.

But, if there’s no rooster, a normal hen will still lay an egg every day. If that egg is taken away by a farmer, that same hen will lay another one the next day, and the next, etc.

Again, the difference here is that the chicken who has eggs when a rooster is around will lay eggs that have been fertilized and will hatch a chicken (eventually). Eggs laid by hens where there is no rooster will not be fertilized and a chicken will never hatch. The eggs themselves are almost identical except for this fact.


What part of the egg becomes the chicken embryo?

It’s called the germinal disc

Many people think that the yellow yolk of an egg is the embryo of a chicken and that we eat these embryos when we eat eggs. In actuality, the yolk is very dense, full of fat and quite nutritious and is the food source for the chicken embryo, not the embryo itself.

The part of the egg that becomes the chicken embryo is called the germinal disc, a whitish spot on the top of the yolk that is visible to the naked eye.

When there is a rooster around and a chicken egg is fertilized, this germinal disc starts to divide into more and more cells, eventually becoming a chick that hatches. When this happens the yolk is there as a food to feed the growing chicken. In fact, the yolk contains all the fat in an egg and that’s why many humans eat the white only, to avoid all the fat.

Speaking of the white of the egg, which is called the albumen, it contains important nutrients for the growing chick as well. That includes proteins that the embryo will need to develop properly into a chick and then an adult hen or rooster, and also water and other liquids essential for life.


Is there sperm in a chicken egg?

Nope, and it’s not even possible. The answer to this question is a definitive ‘no’.

There is no sperm in unfertilized eggs. It’s not possible. The ‘white stuff’ that hangs off the yolk may give the false impression that there is sperm in the egg when in fact it’s the unfertilized germinal disc. This is normal. It’sĀ edible and not harmful in any way.

Whether you purchased your unfertilized eggs at a grocery store or collected them from your chicken coop this morning, there is no chance of them having any sperm as there is no rooster around to provide them.

Again, the reason we domesticated chickens so long ago is that they will lay eggs even if there is no rooster around. Without the rooster, there’s no chance at all that an egg will have sperm in or on it. Plus, even if an egg has been fertilized, there’s no sperm leftover from that process whatsoever and so no chance at all that any egg, fertilized or unfertilized, could have sperm in it.

Is the white in this egg sperm?

By the way, some people are under the false impression that the ‘white stuff’ that hangs off the yolk of an egg is sperm. It is not. These white bits are called chalazae and, in a fertilized egg, they are what holds the yolk in place while the egg incubates and becomes a chick.

Also, the red spot that can sometimes be seen on an egg is the germinal disc which holds all the genetic material the hen will pass down to her chick. It also is not sperm and both the chalazae and germinal disc are edible and not harmful in any way.


Can a chicken lay 2 eggs a day?

Yes, no and maybe.

While there are reports that some chickens lay 2 eggs a day the chance that this happens should physically be very low for several reasons. One of the most basic is simply that it takes from 24 to 26 hours for an egg to form inside a hen. That’s the same time or longer than a full day and so makes it impossible for a hen to lay 2 eggs in 1 day.

On the other hand, you can read reports and blogs from people who keep chickens all over the US and many of them will tell you that, yes, some hens do lay 2 eggs a day and that it is not uncommon at all. Many of these stories talk about how hens will lay more eggs in summer and less in winter. Some say that the younger the hen, the more likely it is that they will lay more than 1 egg per day.

So in short, it is possible for a chicken to lay 2 eggs in a day, as many owners and bloggers can report, even though a normal egg-producing cycle is 24-26 hours long. The general average will therefore still be less than one egg a day.

What is more common than a chicken laying 2 eggs a day, however, is an egg that has 2 yolks instead of the usual one. These ‘double yolks’ as they’re called are no different from a single yolk egg but, for folks who love their egg yolks, can be a delicious extra treat.

So the answer to this question seems to be a resounding ‘maybe’. Maybe chickens can lay 2 eggs a day sometimes depending on the time of year and other factors, and maybe they can’t. But from all the reports I think it’s safe to say that yes, some hens will lay 2 eggs a day and no, some won’t.


Is an egg a dead chicken?

No, and it’s not dead either.

The quick and final answer here is a resounding ‘no’. As we’ve talked about earlier when a hen lays an egg and there is no rooster around that egg will be unfertilized. In essence, it is nothing but proteins, minerals and other bits and pieces of genetic material. It is not ‘dead’ or ‘alive’.

Now, if there is a rooster around and the eggs a hen is laying are fertilized, those eggs can become chicken if they are allowed to hatch. Still, there is no dead chicken inside of a fertilized egg and the egg itself is just the food for what may or may not one day become a chick.

So, again, no, an egg is not a dead chicken in any way, shape or form. Unfertilized eggs that are purchased at a grocery store (or gathered in a private chicken coop) will never become chickens and are nothing more than protein, fat and minerals. Fertilized eggs will grow into a chicken if properly kept until hatching but are not the actual chicken.


Can you eat An egg right after it is laid?

Only if you’re hungry.

If you are keeping chickens in a coop in your backyard one of the biggest questions you might have is whether they can be eaten right away after being laid. The answer is yes, eggs can be eaten right after they are laid, although some people like to clean or boil them first. Still, if you keep a clean coop and the eggs haven’t fallen to the ground it is definitely possible to eat them right away.

One of the best ways to make sure they are clean and ready when you gather them is simply to make sure that the straw is regularly cleaned and laid. That’s not to say that you should clean out all the straw every day and replace it. Instead, pick out any larger pieces of muck, waste or stuff after the eggs are collected. This will allow the hay to stay dry also so that it doesn’t start to rot.

Occasionally, no matter how clean you keep your coop, you will find an egg or two that seems a bit gross and covered with ‘muck’. When this happens you don’t need to wait or throw it away but simply use a dry cloth to remove as much of the muck as possible.


Should you run an egg under water to clean it?

Nope. Dry and rough is how they like it.

Unless you plan to use that egg right away, the answer to this question is no. An egg has a natural coating on its shell called the ‘bloom’, or cuticle. This bloom is the natural protective layer on the egg that shields it from bacteria and other nasty stuff. When you use water to wash an egg the bloom is removed and the egg can then ‘go bad’ faster.

So again, unless you will use your eggs in a recipe right away do not use water to wash them but instead use a dry, rough-ish cloth. Also, keep in mind that you can store fresh eggs for at least 2 to 3 weeks at room temperature, if not more. It’s completely safe and, if the bloom remains intact and isn’t wiped off, it should be just fine.


What is the White stuff when you crack an egg?

Hint; it holds the egg together.

Many times when you crack open an egg you will see white bits of fleshy looking material that some people mistake for chicken (rooster) sperm. This is 100% not correct and, in fact, these white bits are something called chalazae.

The white stuff is called chalazae, and it’s there to connect the egg yolk to the eggshell if that egg has been fertilized, to keep the yolk stable and allow the growing chick to feed on it during incubation. One of the 2 chalazae connects the yolk to the pointy end of the egg and the 2nd connects it to the rounder end. The chalazae are harmless and safe to eat even though many people pick them out before cooking.

Also, the chalazae can be useful. For example, if you see them it is a sign that your eggs are fresh since, after a few days, they will disappear back into the egg. If you don’t see any chalazae then it’s possible that your eggs have been sitting around for a long time and might not be as fresh as you think.


Can you eat eggs with blood spots?

Yes, you can (and it’s not blood).

The answer here is a definite yes, you can eat eggs with blood spots. These so-called ‘blood spots’ are actually the egg’s germinal disc and hold all of the genetic material that the hen will pass on to her chick(s). They aren’t actually blood at all. In most cases, you won’t see them in an egg that was never fertilized so the chance of seeing them is very low,

So yes, you can eat eggs with blood spots on them, although the chance of seeing an egg with blood spots isn’t high.


Why Do Chickens Keep Laying Eggs if they Can’t Make Chicks?

That’s just what chickens do.

As we’ve talked about, when there are no roosters around to fertilize eggs the hens keep laying them anyway. That’s the main reason humans domesticated them so many years ago. The reason they do this is easier to understand if you put it in terms of what humans do.

A human female has to ovulate once a month whether or not she has been with a man or has access to male sperm. This must happen to a woman’s egg every 28 days (on average). In chickens, the process is more or less the same except that they ovulate every day. If a rooster is there or isn’t this ovulation process will still happen. That’s why most hens lay an egg a day even if there’s no rooster to fertilize them.


Can Fresh Eggs Be Stored at Room Temperature?

Yes, as long as the room isn’t blazing hot.

Like me, many people who keep their own chickens wonder if, and for how long, fresh eggs can be kept at room temperature out on the counter or table in their kitchen. The answer is a resounding yes as fresh eggs will stay fresh for 3 to 4 weeks or more without refrigeration.

One thing to keep in mind, however, is that, if the eggs you’re collecting are really dirty and need to be cleaned with water, they should be put in the fridge.

The reason for this is that, when you clean an egg with water, you wipe away something called the ‘bloom’ on the egg’s shell that protects it from bacteria and other nasty stuff. Without the bloom, an egg will ‘go bad’ faster and so should be refrigerated

What many people do is collect egg cartons (we like paper best) to store their fresh eggs. Some also keep a small amount of real straw in a basket in their kitchen and store their eggs there.

By the way, what most people don’t realize is that the eggs they purchase at the grocery store are usually 4 weeks old or older. That’s the average time it takes from the time they are gathered to the time they are delivered to the store, meaning that when you buy them ‘fresh’ they are already a month old in many cases!


How to check if an egg is ‘bad’

Trust me, most are born good.

It is very easy and quick to determine if an egg has gone bad or not by simply placing it a bowl of water. If the egg floats in water it is bad and should be discarded. If it sinks to the bottom it is good and can be eaten, although you should consider eating it right away because now the bloom will have been removed by the water.

Also, as an alternative, you can place the egg up to your ear and shake it gently. If you hear and feel that the egg is ‘sloshing’ around inside it means then the chalazae are gone and the egg is bad. If you don’t, the egg is still edible.

We hope you liked this article on chicken egg anatomy and found it both useful and informative. If you have any questions or would like to leave a comment please do so in the space provided, and best of luck with your chickens!