How to Tell If a Duck Egg Has a Baby in It or Not

To find out if a duck egg has a viable embryo prior to hatching, you can use a technique called "candling" to inspect the inside of the egg. Originally this practice was accomplished using a candle in a dark room to look through the eggshell and determine if a duckling was growing. Today you can use a light box, flashlight, mag light or a candling light designed specifically for the job. There are specific things to look for at different stages of the incubation period to determine the viability of the embryo when candling an egg.

Things You'll Need

  • Light box
  • Flashlight
  • Mag light, 1/2-inch diameter
  • Candling light
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Instructions

    • 1

      Darken the room as much as possible.

    • 2

      Candle the egg using a light box. A light box is a wooden box with an egg-shaped hole cut in the top. A light bulb is positioned inside the box.

    • 3

      Shine a flashlight, mag light or candling light directly into the egg. If the light bounces off the eggshell, use your hand around the end of the light source to redirect the light into the shell.

    • 4

      Candle the egg after eight days of incubation. Look for an embryo with red blood vessels. If the egg is clear, it may have been infertile or the embryo died very early. An embryo with a red blood ring is dead.

    • 5

      Watch for a dark outline on the embryo and ill-defined details between 10 and 16 days as it could signal a late death. Give the egg time and continue to candle it.

    • 6

      Notice a heartbeat, then movement as the embryo grows.