Candling your eggs is a useful step in the incubation process and is also educational and interesting. When you candle an egg, you are using a directed beam of light to see inside the egg. You do this to determine the viability of the eggs in your incubator before they hatch or to get an idea of the development process.
To candle your incubator eggs, start by taking the eggs out of the incubator, gently placing them in an egg carton. Close the incubator so it does not lose too much heat. Turn off the lights in the room. Then working with one egg at a time, hold the large end of each egg against the candler and observe.
It does take some experience and a bit of practice to get a real feel for what you're seeing, but this is a very useful exercise. There are lots of images online or in books that you can use to compare with what you're seeing while candling. You should discard clear or non-fertile eggs or those that have stopped developing.
Tyler, the owner of Purely Poultry, candles his incubator eggs at 18 days old, and then he moves the good ones, where he can see a dark opaque mass, to the hatching tray of the incubator.
Don't leave your eggs outside the incubator for more than 20 or 30 minutes. If the fertility of an egg is unclear to you, carefully mark the shell with a question mark and re-observe it at another time.
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