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How Does a Rooster Fertilize Eggs?

How Does a Rooster Fertilize Eggs?

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Should you want to produce fertilized eggs to hatch more chickens, you will require a rooster to fertilize the eggs. He will need to perform his duties with your hen.

A rooster can fertilize the eggs of up to ten hens. The two must mate so that the rooster’s sperm travels into the oviduct and fertilize the eggs the hen will lay in the next few days.

Therefore, if you want to maintain or expand the size of your backyard flock, you will need a rooster in your coop and ensure that your rooster and hens are mating.

We all know you do not need a rooster for your hen to lay. Your hen can lay an egg with or without assistance from a rooster. 

This article will explain how you can fertilize your hens’ eggs. We will also discuss the steps surrounding the process. Keep reading to find out more.

How Does a Rooster Fertilize Eggs?

Spring Fever- Mating Season

Mating, courtship, and raising brood in chickens start in the springtime. An increase in daylight energizes the hormones. An increase in hormones will then lead to procreation behaviors.

Chickens have the pineal gland in their brain, which detects light increases.

This will stimulate the manufacture of progesterone, estrogen, and androgen, which are responsible for increasing broodiness and egg production in chickens.

The hormones will, in turn, produce a cascade of other hormones required for the development of the yolk and the soon-to-be embryo.

Most of the current breeds of chicken have had the innate ability to become broody bred out of them.

Therefore, only a few of them will sit on their eggs. You will need an incubator if you want chicks and do not have a broody hen in your backyard flock.

Broodiness in backyard chickens tends to be infectious. If you have one hen in your flock that can go broody, you will likely have one more that will want to brood.

The Chicken Courtship Ritual

How Does a Rooster Fertilize Eggs?

Roosters are usually more active in their mating quest during springtime. During this period, they exhibit various courtship patterns.

  • Tidbitting: Tidbitting occurs when a rooster finds a tidbit of food and points it out to its female counterparts. The hen may not give in straight away. However, she will remember the positive move made by the rooster.
  • The Rooster Dance: A rooster will also perform a dance to attract the hen. It drops one wing to the floor and dances around it. As the rooster approaches the hen, he will attempt to hop on board and mate.

There may be no ritual or courtship in some cases, and mating between a hen and a rooster can be aggressive, leaving the hen with injuries.

Dominant Roosters

Male chickens have a pecking order, mostly the fittest and the youngest rooster at the front of the queue.

The rooster on top of the pecking order will fend off interest from other male birds, which may lead to fighting and aggression. The rooster that will be more submissive will run away.

The dominant rooster will be contended by this for around two or three years. As he ages, a young and fitter rooster will emerge and take his space in the pecking order, becoming a secondary rooster. 

Hens usually assess roosters’ ability to stave off other roosters, provide food, and look after the rest of the flock.

Large and colorful wattles and combs are highly attractive to female birds. If a female bird does not like a rooster, she will rarely mate with him, even if he is the only one in the coop.

Secondary Roosters

Secondary roosters in the flock will still mate with their female counterparts. However, it will take a lot of effort, and they may not get the pick of the flock. They must rely on tricks like tidbitting to pick up a hen.


A single rooster can service up to ten female birds. Any more than this, your rooster can become stressed trying to manage the hens.

Fewer hens also mean female birds in the flock will become overworked and battered. 

Even with the ideal ratio of females to males, it is not unusual for your rooster to have one or two favorite females: one that he will return to in preference to others.

These hens may become overused and may develop damaged skin. They may also show loss of feathers around the neck and the back.

You can prevent this damage by placing hen saddles on the favorites in the flock.

How Do Chickens Mate


The actual mating process in chickens is usually quick. When the courtship is completed, the male chicken will hop on the back of the hen.

She will squat and slightly drop her head and body if the hen complies. She will also show her willingness by spreading her wings.

On the other hand, the rooster will tread to help him get balance. He will also grab the comb to further steady his balance.

The Cloacal Kiss

Once the male is in a good position, he drops his tail and delivers a cloacal kiss. Roosters do not have a penis.

Instead, they have a bump called papilla, located inside the cloaca. It is this bump that delivers the sperm inside the reproductive system of the hen.

The hen will extend her cloaca for the sperm to reach the waiting eggs. The sperm delivered will fertilize the day’s eggs; some will collect in sperm pockets.

It can then fertilize eggs for the next few days. Once the mating process is over, the rooster will walk away. On the other hand, the female will collect herself and carry on.

Chicken Reproductive Anatomy


A male chicken has two testes in his abdomen close to the kidneys. Roosters are always ready to manufacture sperms as needed for mating.

However, they do not have a penis. Instead, they have a papilla inside the cloaca. The testes usually deliver the sperm to the papilla through the vas deferens, which then deliver it to the hen’s cloaca.


Hens are usually born with two ovaries. However, the right ovary usually atrophies and dies. Therefore, the left ovary will carry all the eggs a hen will ever lay in her lifetime. 

The ovary has hundreds of egg follicles, which include the ripening chicken egg. When the egg is ready to be dispatched, it will be dropped into the infundibulum of the oviduct. Here, it will begin its descent.

The Journey

The sperm is deposited in the hen’s cloacal area and migrates into the vagina. Here, it can stay in “pockets” on the wall.

The sperm is viable inside the pockets for 6 to 9 days, although the fresh one is the best.

Sperm intent on fertilizing the egg travels up into the oviduct area known as the infundibulum to ensure success.

A chicken’s oviduct is about 30 inches long, and the sperm travels about 28 inches to reach the infundibulum to deliver the genetic code to the egg’s germinal disc.

Once the DNA of the rooster is delivered to the hen DNA, they fuse and develop into a zygote.

It usually takes about 5 hours for cell division to start. At this point, it is called an embryo or blastoderm.

Cell division and expansion will go on unabated as the fertile egg undergoes all the necessary stages to make an egg.

The stages include laying down albumin, building the eggshell, and applying the bloom.

If the hen wants to be a mother, she will find a nesting place that is dark and quiet. After that, the hen will cache her eggs until they are enough for incubation.

The number of eggs in a cache is usually variable. However, you must ensure that your hen can cover all her eggs. Six to nine eggs is a reasonable number.

If the eggs are too many, you can remove some and place them in an incubator or another broody hen.

Development And Brooding

If you want your hens to hatch their own, there are a few things to do to make the process smooth and successful. 

First, you must ensure the rooster does not hurt the hen during mating. You should trim their talons and spurs and even use a hen saddle if necessary. 

When your hen is looking for a secure and dark place to set, you can encourage her to a separate place where she will be comfortable and not disturb the other birds.

You will also have to add a waterer and a feeder. The area should be fully secured and safe from predators.

Once the hen has enough eggs, she will start to brood. She will sit on the eggs for about 21 days until they hatch. Remember that not all hens will go broody.


Roosters are usually sexually active from several months after birth. They ensure the flock’s survival by mating with their female counterparts and fertilizing eggs.

They may employ courtship rituals like rooster dancing and tidbitting. You are now answered if you have been wondering how roosters fertilize eggs.

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