Without a rooster, a hen can still lay eggs just fine, but the eggs are not fertilized, and they won’t grow into baby chickens. Naturally, the rooster needs to mate with the hen to fertilize her eggs.
But, with many egg-laying facilities and farm chickens, the roosters are not present at all, so is there a way to fertilize eggs from those chickens?
How to fertilize chicken eggs without a rooster?
For now, there isn’t any reliable and easy way to fertilize the eggs without the rooster. The rooster mates with the hen to fertilize the eggs prior to the formation of the eggs.
How is an egg fertilized?
The rooster’s role
A rooster and a Hen
Roosters have testes – the reproductive organs – that produce sperm just like most mammals. The sperm travel down through the vas deferens tubes to the sperm sacs.
During less than 20 seconds of mating, through an opening known as a cloaca, the sperm leaves the male body. It then goes through the entrance to enter the female and reach its oviduct – the female’s reproductive tract.
Once inside a hen, the sperms go through the hen’s reproductive organs. They go through the hen’s shell gland, then the isthmus – the hen’s reproductive tract, the magnum, and the infundibulum.
The moving process takes about a week or more. Now they only have to wait for the formation of the egg inside the hen.
The hen’s role
The process of forming an egg starts as yolk in the ovary. The yolk is then released and then goes into the infundibulum, where the sperms are waiting.
This is when the sperm goes to the yolk and the egg is fertilized. They then go out of the hen through the same route that the sperm entered.
The white starts to form around the yolk in the magnum. The shell membranes are laid down in the isthmus. Then in the shell gland, it forms and hardens.
The egg is now ready to be laid, but the hen may hold it until morning. After laying for about half an hour, the next egg is ready to form. The remaining sperm inside the hen can be later used for fertilization for about a week or more.
Roosters are needed for fertilization
How do farmers know if an egg is fertilized?
Usually, the farmers will sometimes use the candling method, which is done by holding the egg in front of a bright light source. If there is a dark spot, then that egg is fertilized.
The above method can be done when the egg reaches day 4. However, the most accurate method is by cracking the egg and look for the white spot on the yolk:
If there is a light-colored dot with an irregular border, then the egg was not fertilized. That irregularly shaped dot is the blastodisc – the hen genetic material.
If the dot has a bullseye appearance with a regular concentric shape, then the egg was fertilized. That dot is called the blastoderm, which is what the blastodisc turns into when the egg is fertilized.
Alternatively, if you got your eggs from a store or a supermarket, there is a high chance that those eggs are not fertilized since they often come from an egg-producing facility. This place usually doesn’t keep roosters around.
With the hens, after sitting on the unfertilized eggs for about 10 to 14 days, it could sense something isn’t right with the unfertilized eggs and could possibly leave the nest.
Do you need a rooster for the egg to hatch?
You don’t need to have a rooster for the hens to lay eggs. The egg can still be formed without being fertilized by the rooster. However, you need the rooster mating with the hens to fertilize the eggs to hatch.
How do you grow an open egg?
You may think once an egg is cracked or broken, there is no hope of saving the egg. But there are people that have succeeded in cracking and hatching the eggs outside of its shell.
A group of Japanese students cracked the egg, dropped it into a plastic pouch, and incubated it. A few days later, a baby chicken emerged. (source).
They perform the technique mentioned in their study published in 2014, where they took out a chick embryo and cultured it in an artificial environment.
However, this method is not ideal for commercial use yet since it is very tricky to perform. The natural eggshell environment is hard to replicate, which acts as a protection, a food source, and a filter for the embryonic chicken.
Moreover, the shell provides the embryo with minerals like calcium, manganese, and magnesium. So the artificial environment needs to supplement those minerals as well.
The shell also prevents the inside from being infected by bacteria. Therefore, it needs an aseptic and clean environment in the lab.
The embryo container needs to be porous since, in a normal egg, there are pores all over the shell to allow carbon dioxide to exit and oxygen to enter.
Finally, the shell-less egg needs to be warm, which those students achieved by placing the egg into an incubator.
Conclusion
So, how to fertilize chicken eggs without a rooster? So far, only the natural method is considered optimal when it comes to fertilizing eggs. That is the rooster mating with the hen to fertilize the eggs before they start to form.
If you want to know if the egg is fertilized, crack the egg and look for the blastoderm with a white bullseye dot.
Or if you prefer not to break the egg, put it in front of a bright light source and look for the dark spot. That is the indicator of fertilized eggs.
Resources
Image credits – Photo by Jonathan Koh, Verstappen Photography on Unsplash