Why Do Chickens Lay Unfertilized Eggs?

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As a chicken farmer, you may be looking forward to petite, fuzzy baby chicks running around, but for some reason, your hens are failing to yield fertilized eggs. There are many factors that go into hens laying fertilized eggs. 

A mature hen will lay an egg just about every day, to every other day, regardless of whether it is fertilized or not. However, the most crucial fact to remember is, if your hens are not mating with your roosters, for whatever reason, the eggs they lay will be infertile.

Let’s take a deeper look at why your hens could be laying unfertilized eggs and come up with some possible solutions to help encourage your chickens to mate and fertilize more eggs. 


Will Hens Lay Eggs Without a Rooster?

Yes! A hen can and will lay eggs without a rooster. Nutrients from the food hens eat become the building blocks for egg yolks, where the chick is formed. The yolk is created first, then the white forms, which is the nutrients that will feed the chick from fertilization to birth. The recommended diet for a hen to produce healthy, fertilized eggs are:

  • 1/3 protein
  • 1/3 fat
  • 1/3 water

The process of an egg being formed begins in the ovary, where the yolk is formed:

  1. Tiny tissue bags, called follicles, fill with yolk and grow. The largest follicle will yield first, then the next largest, and so on. 
  2. The infundibulum catches the largest yolk and sends it through the oviduct, where fertilization will occur. (approx. 15 minutes)
  3. The egg will then spend about 3 hours in the magnum, where albumin, the egg white forms.
  4. The egg then travels through the isthmus, where shell membranes and proteins are deposited around the egg.
  5. Twenty hours in the shell gland is where the shell forms. Crystals of calcite grow around the outer membrane and form the shell.
  6. Oviposition then causes the egg to rotate, and contractions push the egg out of the body. Hens body temperatures are about 106 degrees Fahrenheit. As the egg cools after being laid, an air pocket forms in the egg, which the chick will then puncture and breath before hatching.
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Regardless of whether a rooster has mated the hen, she will still lay eggs. Hen’s bodies are built to form eggs naturally, even without the presence of a rooster. Mature hens will continue to lay about every 24 to 48 hours.


How Do You Differentiate Between Fertilized Eggs and Unfertilized Eggs Without Cracking Them?

MethodSigns of fertilization
Candling the egg – this is the easiest method. This method is when you hold the egg up to a very bright light or a lit candle to see the egg’s inside.If the egg appears to be cloudier or opaque than the other eggs, it is most likely fertilized.

Four Reasons Why Your Hen May Be Laying Unfertilized Eggs?

You Don’t Have a Rooster!

Without having a rooster to mate with, your hen will not receive the sperm it requires to reproduce a fertilized egg, unlike other egg-laying creatures. Birds need their eggs to be fertilized while still inside their reproductive system, and without sperm from a matured rooster, fertilization is impossible.

You may be asking yourself, “How do I know if I have a good rooster?”.

Well, a good rooster will always introduce himself to the hen with something called a “chicken dance”. By doing this, your rooster is asking the hen to squat down.

This dance can look like several gestures, but it often involves the rooster ruffling his feathers, turning sideways, and flapping his wings. This signals the hen that it is time to mate. 

On the other hand, a mean rooster won’t perform the dance. They will just forcefully jump on the back of the hen, bite their neck, and force them into the ground. If you catch your rooster doing this, it might be time to get a new rooster, as this can cause stress on your hens and cause defects in your eggs.

Your Ratio of Hens to Roosters May Be Off.

Experts typically recommend having about one rooster for every ten hens. Having multiple roosters is acceptable in larger flocks. Just keep in mind that the leading rooster, or “top rooster”, will claim all or most breeding rights.

In other words, he is the alpha male who gets to breed first. His sperm will typically supersede the other roosters in fertilizing the eggs.

You should also keep in mind that if you choose to keep multiple roosters, they may tend to get aggressive towards one other, fighting for the top rooster position. This can also lead to overbreeding or even aggressive mating with your hens. This may result in higher stress for your hens, eventually leading to unhealthy yields and possible egg defects.

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You May Find That Your Hen is Fighting Off Your Rooster(s).

Your Hen is Fighting Off Your Rooster

If you are trying to introduce a new rooster to a flock of hens, you may find that they are fighting him off. Another instance may be if the hen is protecting her baby chicks from a rooster.

A third reason your hens may fight a rooster is if he has a habit of mounting them aggressively to mate. Sometimes, roosters can get a bit bossy and harass your hens to assert dominance and fertilize them to grow their flock.

Your Hen is Rejecting Sperm.

Chickens are pretty smart. Hens have deep glands within their oviduct, where sperm from roosters is stored for up to 14 days. Hens’ bodies have a natural way of ejecting sperm from “unfit roosters”.

If hens are particularly stressed or malnourished, they may also reject sperm. Their reproductive system’s goal for rejecting and keeping certain sperm is to reproduce with the top rooster, or the alpha rooster, as this will produce the healthier, stronger flock.


How to Encourage Your Chickens to Mate and Fertilize More Eggs.

The number one thing to remember when trying to grow a healthy flock is to maintain a healthy, well-balanced diet for your chickens. A safe and stress-free habitat will also promote a healthier flock. Below is a list of tips that will also help yield the best results when it comes to promoting the fertilization of eggs.

  • Limit the number of roosters to eliminate as much competition and encourage more fertilization by the top rooster.
  • Remove roosters older than six years old, as their fertility decreases with age, and eventually, they will become infertile. These top roosters may continue to dominate the other roosters but with little to no fertility yield.
  • Be sure to provide a safe and healthy environment for your flock, as unclean and predator-infested environments can cause stress and possible infertility. Your roosters are also there to protect your hens, but they can’t be their only defense.
  • Finally, as stated earlier in this article, a well-balanced diet will promote fertility and the urge to reproduce.
how to encourage your chickens to mate and fertilize more eggs

In conclusion:

It’s a natural duty of a hen to keep laying eggs. If your hen has never been around a rooster, then for sure, the eggs would be infertile.

There are many factors that go into growing your flock and encouraging more fertility among your chickens. Key things to remember:

  1. Safe, clean, stress-free habitat.
  2. An appropriate ratio of hens to roosters
  3. Well-balanced diet: food, nutrients, water
  4. Make sure you have a good, fertile rooster that protects your hens, as well as respects your hens during the mating process, rather than attacking them.