Crowing is an individual thing, they can crow as early as 4 weeks and as late as 20 weeks. Mine started at about 12-15 weeks I think? At this age you should be able to tell genders.I think I may have lucked out. Got 12 day olds July 15th. Supposedly seed pullets. NONE are looking/acting rooish-yet. How old til they crow? Mine are now 9 weeks and still chirping.