How are chicken eggs fertilized

How Are Chicken Eggs Fertilized? 5 Ways Explained

We all understand that you do not need a rooster to get an egg. Our hens will lay an egg every day with or without any help from the male chickens.

However, in case you need to fertilize the chicken eggs, you’ll need a rooster to carry out his responsibilities with your hens.

For a hen to lay fertilized eggs, she desires a rooster. The rooster will fertilize the eggs of up to ten hens. He should mate with the woman hen so his sperm travels into the oviduct. This will then fertilize the eggs that the hen lays in the following couple of days.

If you’re seeking to expand or maintain the dimensions of your flock, you may need a rooster and you’ll need to make sure that your hens and rooster are matings.

How does a rooster fertilize an egg?

  1. First of all, roosters do the mating dance in front of the hen. 
  2. It will then circle the hen and start moving feet with wings stretched down. 
  3. The roster will now scratch the ground with its feet. This is its way to tell the hen that this is the time to mate.
  4. The female will crouch and flatten its back so that the rooster can mount her. He may bite the feathers on the head and neck to maintain the balance on top of the hen. 
  5. The hen will lift the tail feathers and the rooster will go low so that he can do his work. This is called as “Cloacal kiss”

11 Facts About Fertile Chicken Eggs

  1. Supermarket eggs are not fertile
  2. Having a rooster doesn’t assure egg fertilization
  3. Not all roosters are fertile
  4. It can take some time after mating for hens to end up fertile
  5. Hens can stay fertile for a while after mating
  6. Eggs are exceptionally hot
  7. Hens are probably able to inform which eggs are healthy
  8.  Eggs include the whole lot for chick development
  9. Candling will let you see if an egg is fertilized
  10. Unfertilized and Fertilized eggs taste the same
  11. The color and form of the egg don’t have anything to do with fertility

Fertilized Vs Unfertilized Chicken Egg Comparison

The foremost distinction between fertilized and unfertilized eggs is the rooster’s part withinside the procedure. If a chicken mates with a rooster, then the eggs the chicken lays may be fertilized.

If not, the chicken will lay unfertilized eggs. Regardless of the rooster, the chook will drop the eggs. Any fertilized eggs will then require the right incubation in order to emerge as chicks.

Thus, as soon as you refrigerate the egg, the fertilization procedure stops. So in case, you had been to consume a fertilized egg, you likely would not notice the distinction!

If this query makes you wary of purchasing eggs, you do not need to worry. Most eggs you purchase at the grocery shop are unfertilized!

And in terms of taste and texture, fertilized eggs are not much distinct from unfertilized eggs. And the nutrients are precisely the same!


Before you crack an egg, you could tell if it is a fertile egg through the candling process. During this process, you go right into a dark room, and light is shown at the egg so one can see withinside the egg.

Around the 4th day of fertilization, veins will start to appear around a darkish spot in the center of the egg. This is one way to tell if it is a fertile egg before cracking it.


After you crack an egg, the way to tell if it is fertile is to examine the yolk.

Unfertilized eggs may also have a white dot. However fertilized eggs may have a concentric circle across the white dot. In other words, the white dot may have a bullseye appearance.

Chicken Egg Fertilization Timeline

When a rooster mates with a chicken, the storage tubules (SSTs) store the $emen. These tubules are present in the vicinity wherein the chicken’s uterus joins the vag!na. That is, provided the chicken likes the rooster. If she does not, she will be able to squirt out the $emen to avoid hatching his offspring.

Assuming the chicken approves of the rooster, the SSTs save the rooster’s $emen. The hormone progesterone then launches the sperm. The hen’s body releases this hormone when the chicken lays an egg.

The subsequent ovulation would not arise for approximately 5 hours, giving released sperm lots of time to wiggle through the oviduct, without interference from a descending egg. This is to fertilize the subsequent growing yolk.

Since the sperm launches rapidly after an egg is laid, and every egg takes about 25 hours to develop, a hen that produces an egg on the day of mating will now no longer be fertile. An egg laid tomorrow may or might not be fertile, relying on the timing. An egg laid on the third day really needs to be fertile.

The quantity of time during which the chicken will preserve to lay fertile eggs relies upon how much sperm fills the SSTs. These are able to store $emen from multiple matings and more than one roosters. Highly efficient hens commonly stay fertile longer than hens that lay at a slower rate. Also, single-comb breeds stay fertile longer than rose-comb breeds— possibly so long as a month. However, that’s surely rare.

The common duration of fertility from a single mating is 10-14 days.

If you want to hatch eggs from a particular chicken and a particular rooster, you could be 100% of the “right” fertility by first housing the chicken away from any roosters.

After approximately 10 days, start checking her eggs for fertility. An egg that isn’t fertile can have a faded irregularly shaped spot of cells on the floor of the yolk. In a fertile egg, the cells prepare into certainly visible concentric rings, like a tiny bullseye.

Another way to decide an egg’s fertility is to incubate it for some days, then either candle it or crack it open to test for embryo development.

When a chicken has laid at least infertile eggs in a row, you could be quite sure her SSTs are clean of sperm. Many hen keepers, to guarantee fertile eggs are from the preferred mating, surely put the chicken and rooster together. Then they wait 2 to 3 weeks before gathering the eggs for hatching.

How Can You Tell If A Chicken Egg Is Fertilized?

When you crack open the egg, if it is fertile, you will observe a small white spot at the pinnacle of the yolk about 4mm in width. This is known as a germinal disc. This tells you if it is a fertilized egg or not.

A single cell from the female and a single sperm from the male form this disc. The female cell carries 1/2 of the number of chromosomes and the male, the other 1/2.

After fertilization of the 2 halves, the ensuing cell divides and these cells develop and divide once more until the hen lays the egg.

During incubation, this mass of cells will further develop, divide and specialize to form the ensuing chick, the use of the rest of the egg contents as food.

Frequently asked questions

Do We Eat Fertilized Eggs?

Fertilized eggs are absolutely safe to devour—except you have neglected to take care of them or wash the egg. Or you have allowed your broody chicken to have her eggs for longer than normal. You can thoroughly devour your fertilized eggs without any worries. It is truly no more special than an unfertilized egg.

Can Chicken Eggs Be Fertilized After They Are Laid?

The hen does not lay fertilized eggs. For a hen to put fertilized eggs, she needs a rooster. The rooster will fertilize the eggs of up to ten hens.

How Do Farmers Know If A Chicken Egg Is Fertilized?

Farmers sometimes candle eggs, which includes keeping them in front of a shiny light in a dark room to search for dark splotches, which show a fertilized egg.

Final words

In conclusion, I would say that the fertilization process is something that totally depends on the hen. It is the decision of a hen if she wants to process the sperms or squirt them out. Also, not all roosters can fertilize the egg. This makes the fertilization process a bit difficult.

I hope you enjoyed the article. We will be back with more interesting and informative pieces of writing. Till then, stay connected. Thank you.