I breed Black Rat Snakes, and the average number of eggs in a clutch is 12, though I have had one lay as many as 23 eggs, or as few as two. Not all of the eggs will hatch; most of the time there will be at least one or two that are infertile and will rot. Sometimes baby snakes fail to hatch and die inside the egg or die right after hatching for no apparent reason, even in captivity. In the wild, most of the babies in a clutch will be killed before they reach a year of age, and probably only two out of each dozen will make it to adulthood.