Seaslug
Songster
In general, the pullets have combs that are smaller and remain pale in color for multiple weeks after hatching, while the males will grow larger and color up at a much younger age. But it is a generality, because some breeds do not follow the "rules" (silkies, apparently), while in others it can be relative, like some breeds do not have large combs at any point and some can have early large combs in pullets. And, of course, each animal is an individual. But using comb color and size is one of the more reliable ways to sex young chickens for the amateur.
