How can you tell if the eggs you are incubating are fertile or not?
There’s a method called “leopard gecko egg candling”. It’s simply to shine a light on the egg to see if the egg gives off a pink/red color or not. A fertile egg will usually give off a pink, reddish look on the inside. It’s an indication that there’s something growing inside. Here’s an example from one of our eggs, this egg has been incubating for 30 days now.
This particular egg is being incubated for females at 81(F) degrees, so it has another 30 days to go yet. But you can see very distinctively the pink/reddish coloration on the inside.
For infertile eggs, they will likely look pale yellow with no red color. But like the old saying goes, “incubate until there’s no debate”. It’s always best to incubate until the egg grows mold, deflate, or smell bad. You just never know, some eggs take a long time to hatch.
Some people like to take their eggs out to candle them. Personally I advocate leaving the eggs alone. The less you disturb it, the better off it’ll be. Each time you take the eggs out, the humidity and temperature drops. As you can see from the picture above, you can candle an egg without taking it out of its incubation container. We actually took this picture without even opening the incubator.
Hope this helps, let me know if you have any questions.