You may have hatched some baby chicks in spring and now have some teenage chooks and are wondering which are boys and which are the girls. This is hard until they get their adult plumage and are around 2-3 months old. One of the only failsafe ways is if it starts to crow it is a boy! These are some of the ways I try and guess. The males will have a larger tail, often with a green tail feather. The males will be bigger and their combs may be bigger. If you startle them the males will often stand tall on their legs while the hens will crouch down.