What determines hatching gender? Any tips?

[Canadian Wind]

Actually, you have it backwards, Canadian Wind. The hen's ova determines sex in chickens, not the sperm from the male. Weird, huh? I have found this information on many different sources. Here is one example:

"Avian sex differentiation is not determined by XY chromosomes like it is in humans and most mammals (or even the XO system used by some insects). In those systems the sex is determined by the sperm, by what the male contributes to the offspring. By contrast, birds have a ZW system of sex determination (shared with butterflies, moths, fish and reptiles). In that system, sex is determined by the female within her ova, and the sex of offspring is not affected at all by the sperm which the male contributes. Some people think it is this difference which makes parthenogenesis possible for birds. Parthenogenesis occurs when unfertilized eggs see embryonic development." -- My Pet Chicken

Yes, this was already pointed out and explained to me.