How Do I Know If My Chicken Egg Has Been Fertilized?

When attempting to hatch chicken eggs it's important to inspect the eggs periodically throughout the incubation period to be sure the egg has an embryo and that the embryo remains viable, especially when using an incubator. Infertile eggs left in an incubator can become "bangers" --- eggs that are rotten and might explode. Bangers create a smelly, potentially unsanitary mess in the incubator. "Candling" is the technique of using a light source to inspect eggs to monitor the progress of the chick inside. Eggs should be checked throughout the 21-day incubation process to ensure an embryo is still developing.

Things You'll Need

  • Dark room
  • Flashlight, mag light or candling light
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Instructions

    • 1

      Darken the room where you plan to inspect eggs. The room should be as dark as possible to get the best view inside the eggs. Choose a space close to the incubator. You will want to get eggs inspected and back into the incubator as quickly as possible to avoid cooling.

    • 2

      Shine light from a flashlight, mag light, special candling light or other light source directly into the eggshell. You can use any direct light source to inspect the eggs, but be careful with any hot light source. Even brief exposure to 104-degree heat or higher will kill the embryo inside the egg.

    • 3

      Inspect eggs after eight days of incubation. A dark spot in the large end of the egg surrounded by a faint outline of blood vessels is a live embryo. If the inside of the egg is clear, it's infertile and should be removed from the incubator.

    • 4

      Candle again on days 14 and 18 of the incubation period to check for "quitters." Quitters are eggs that were fertilized but don't develop or die in the incubation process. This is a normal occurrence; eggs that aren't developing should be removed from the incubator. The living embryo will continue to grow and progress. By day 14 you may even be able to see movement inside the egg.