If you keep chickens or are curious about hatching chicks, one question probably pops up often: How do you know if a chicken egg is fertile? It’s a great question because fertile eggs are the ones that can develop into baby chicks, while infertile eggs won’t. The good news is, there are simple ways to tell if your eggs are fertile without needing fancy equipment. Let’s dive into the details in a friendly, easy-to-understand way!
What Makes an Egg Fertile?
First, a quick biology lesson: a chicken egg is fertile if a rooster has mated with the hen before she laid the egg. The rooster’s sperm fertilizes the hen’s egg inside her body, which means the egg has the potential to develop into a chick if incubated properly.
If you don’t have a rooster around, then your hens’ eggs are definitely infertile. But if you do have a rooster, most of the eggs your hens lay will likely be fertile, especially if the rooster has access to the hens regularly.
How to Tell If an Egg Is Fertile Without Cracking It Open
1. Candling the Egg
Candling is a popular, non-invasive method to check if an egg is fertile or developing. You simply hold a bright light (like a flashlight or even your phone’s light) up to the egg in a dark room. This lets you see inside the egg.
– Fertile eggs will show visible signs of development after a few days of incubation, such as tiny veins, a dark spot (the embryo), or a shadowy mass.
– Infertile eggs will appear clear or just have the yolk visible without any signs of growth.
This method is especially useful if you want to hatch chicks and don’t want to break the eggs.
How to Tell If an Egg Is Fertile by Cracking It Open
If you don’t mind cracking an egg, this is the easiest way to check fertility:
Look for the “Bullseye” on the Yolk
Every chicken egg has a small white spot on the yolk called the germinal disc. In unfertilized eggs, this spot is small and plain, called a blastodisc. But in fertilized eggs, this spot looks like a tiny bullseye or target with concentric rings around it, called a blastoderm.
– The blastoderm is larger, less dense, and has a clear white ring around the center spot.
– The blastodisc is just a small white dot without rings.
This bullseye pattern is the telltale sign that the egg is fertile and capable of developing into a chick if incubated.
How Long Does a Hen Lay Fertile Eggs After Mating?
Once a hen mates with a rooster, she can store sperm inside her body for up to two weeks. This means she can lay fertile eggs for about two weeks after just one mating session. So, if you introduce a rooster to your hens, you can expect fertile eggs starting from the second day after mating and continuing for a couple of weeks.
Other Interesting Facts About Fertile Eggs
– Fertile and infertile eggs look the same on the outside. You can’t tell by just looking at the shell.
– One rooster can fertilize eggs from many hens — sometimes a dozen or more — so you don’t need multiple roosters for a fertile flock.
– If you’re incubating eggs, fertile eggs will lose some weight over time due to water loss, as the developing embryo uses the egg’s contents.
Quick Tips for Checking Fertility
– If you have a rooster with your hens, most eggs are likely fertile.
– Use candling after a few days of incubation to see if embryos are developing.
– Crack open an egg and look for the bullseye on the yolk to confirm fertility.
– Remember, infertile eggs have just a plain white dot on the yolk without rings.
Knowing how to spot fertile eggs helps you decide which eggs to incubate for hatching or simply satisfy your curiosity about your flock. Whether you use candling or the bullseye method, it’s a fun and rewarding skill to learn!
Fertile eggs hold the promise of new life — and now you know how to recognize them!