the eggs of most turtles will look bad if infertile just like snake eggs. yes turtle eggs are a little more hard but keep humid just as you do snakes.The kingsnake,cornsnake, & anole eggs all incubated similar to the various turtle species I breed/bred. For the most part mold or smell will tell you if the are bad.I don't know why but turtle eggs don't seem to candle as well as snake eggs,possibly due to how the embryo developes.