Chickens: How Does a Rooster Fertilize an Egg?

This maybe an awkward thing for many to ask about but this bird question is asked so often! How does a rooster fertilize an egg? How do chickens become pregnant? Do hens have to mate in order to lay eggs? Dr. Jess explains it all below…

Do Chickens Mate?

The question you really are wanting to know is:

How do chickens reproduce? Do chickens have sex?

Just how do chickens mate?

Can Hens (Female Chickens) Get Pregnant?

Hens do not get pregnant.

Instead, chickens lay eggs which can be fertile or not fertile depending on if the rooster has the opportunity to fertilize this situation.

I'll explain more below…

Let's Talk Chicken Eggs:

Chicken bird eggs come in many different shapes, sizes, and colors.

Most of the eggs that you find at your neighborhood grocery store are either white or brown in color.

The most commonly seen grocery store eggs are usually medium, large, or jumbo in size and have a ovoid shape to them.

If you break through the hard shell of a chicken egg you will find the egg white and the yellow or orange egg yolk, the two parts of the egg that most humans consume.

Do Chickens Have to Mate to Lay Eggs?

Hens lay eggs whether or not a male is around. 

Female chickens do not need roosters around to mate with them in order to lay eggs.

That's why many chicken owners have only hens yet they still produce beautiful unfertilized eggs to eat.

Basically – if there was no rooster around, the hens would lay eggs anyway, but the eggs would never hatch into chicks.

How Do Chickens Mate?

It all starts with a mating dance mostly performed by the flamboyant moves of the rooster.

The rooster will circle the hen while moving his feet with his wings stretched down.

He’ll also scratch the ground with his feet.

It’s the rooster's way of letting the female chicken know that it's time to mate and that he is marking “his territory.”

The hen will likely crouch and flatten her back for the rooster and hold still while he mounts her. He will likely bite down on the feathers of the hen's head and neck for balance.

The hen's tail feathers will lift up and the rooster's will be lowered so their vent or cloacas touch, called the “cloacal kiss.”

This is how the sperm is passed from the rooster to the hen.

How Long Does Chicken Mating Take?

The whole process takes only a few seconds from start to finish.

What is the Cloaca?

Just what is a cloaca?

A cloaca is a part of a bird. It is the one entrance and exit hole through from which they urinate, defecate and transfer sperm.

Unlike most mammals, a female chicken has only one rear hole that performs three important functions. It is the exit point for feces and eggs and the entry point for sperm to enter.

The rooster’s cloaca has two functions, to pass feces and to transfer sperm to a hen.

Does a Rooster Have a Penis?

To answer this question – a rooster does not have a penis.

Instead, roosters have a small bump inside their cloaca called a papilla where the sperm are delivered to the hen.

A rooster may mate between 10-30 times per day depending on the rooster.

A roosters sperm count can be anywhere between approximately 150 million and about 5 billion sperm.

How Do Chickens Get Pregnant?

A rooster does not impregnate a hen.

If a female is not impregnated, then she can not be considered “pregnant”.

Instead, the hen will lay eggs that can either be fertilized by the rooster or will be unfertilized because the roster did not mate with the hen.

In the later case of there not being a mating and there are unfertilized eggs, those eggs will be the ones that you see sold on grocery-store shelves.

The fertilized eggs will grow a baby chick inside and will eventually hatch a chick if healthy and successful.

How Do Roosters Fertilize Eggs?

So just how are chicken eggs fertilized by rooster?

Once the sperm is in the hen’s body, it is held in the oviduct.

Then, as the egg leaves the ovary and enters the oviduct, the sperm joins with the ova (the egg) and fertilization occurs.

A hen who was mated by a rooster can store sperm in her body and her eggs will be fertile for at least a couple of weeks and sometimes much longer before she needs to re-mate.

The stored sperm is collected in sperm pockets located within the walls of her oviduct to fertilize more eggs later on.

What About The Chicken Eggs?

The egg will not develop until certain conditions are met.

The most important of these conditions is that the egg is at approximately 99 degrees Fahrenheit for 24 hours or more for a viable egg outcome.

Resources:

• Avian Female Reproduction Challenges: How It Works and Why It Doesn’t Conference Proceedings : Southwest Veterinary Symposium : SWVS 2018. Stephen Fronefield
• Introduction to Pet Chickens, Diagnostics, and Therapeutics Conference Proceedings : Atlantic Coast Vet Conference : ACVC 2015. Brenna Fitzgerald