Knowing whether a chicken egg is fertilized is simple if you know what to look for. This knowledge can help if you’re raising chickens and want to hatch chicks.
Below, we will explain the key signs of a fertilized egg and how to identify them.
What Is a Fertilized Egg?
A fertilized egg is one where a rooster has mated with a hen, allowing the egg to develop into a chick. If you don’t have a rooster in your flock, the eggs your hens lay will not be fertilized.
Fertilized eggs contain an embryo that, given the right conditions, can grow into a chick. However, to the untrained eye, a fertilized egg may look the same as a non-fertilized one.
Early Signs: The Germinal Disc
The first thing to check is the germinal disc, which is the small white spot on the yolk. In a fertilized egg, this disc contains a tiny embryo that appears as a bullseye pattern—a white circle with a clear center. In a non-fertilized egg, the disc is just a small, solid white spot without a clear center.
To see this, you need to crack the egg open carefully. Place the egg in a bowl and observe the yolk closely. If you see the bullseye pattern, the egg is fertilized. If the white spot is tiny and solid, the egg is not fertilized.
Candling the Egg
Candling is another method to check if an egg is fertilized without breaking it open. This technique involves holding the egg up to a bright light in a dark room. You can use a flashlight or a specialized egg candler.
Hold the light source close to the egg and rotate the egg slowly. In a fertilized egg, you may see a network of veins or a dark spot inside the egg after about 4 to 7 days of incubation. These veins are the developing blood vessels, and the dark spot is the developing embryo. A non-fertilized egg will appear clear, with just the yolk visible.
Monitoring Development
If you’re incubating eggs, it’s important to monitor their development. Fertilized eggs will show clear signs of growth. By day 7 of incubation, you should see a small embryo forming when you candle the egg.
By day 14, the embryo will be larger, and you should see movement. A non-fertilized egg will not develop and may start to spoil.
Differences in Taste and Nutrition
It’s worth noting that fertilized eggs taste the same as non-fertilized eggs. There is no significant nutritional difference between the two. This means you can eat fertilized eggs just like you would non-fertilized ones. The only difference is that a fertilized egg has the potential to become a chick if incubated.
Handling Fertilized Eggs
If you plan to hatch chicks, handle fertilized eggs with care. Store them in a cool place, ideally around 55°F (13°C), and rotate them daily if you’re not incubating them right away. Do not wash fertilized eggs before incubation, as this can remove the protective bloom that helps keep bacteria out.
Common Misconceptions
Many people think that eggs bought from the store can be fertilized. This is not the case. Commercial eggs come from hens that are not exposed to roosters, so they are never fertilized. Only eggs from hens that have mated with roosters can be fertilized.
Another misconception is that you need to refrigerate fertilized eggs right away. If you plan to hatch them, it’s better to store them at room temperature until you’re ready to incubate them. Refrigeration can reduce the chances of successful hatching.
Final Thoughts
Telling if a chicken egg is fertilized is straightforward once you know what to look for. Check the germinal disc for the bullseye pattern, use candling to monitor development, and handle the eggs carefully if you plan to hatch them. With these tips, you’ll be able to confidently determine whether your eggs are fertilized and on their way to becoming chicks.