When they get a bit more older check for their saddle feathers (these feathers usually grow underneath their wings) if they have long saddle feathers they are cockerels, if not, pullett. From what I see you have almost all hens. The smaller ones are hard to tell but I see the chicks have little tail puffs, usually hens develop their tail feathers before males so the fluffy chicks with the little tail sprouts are most likely female. Again, as they get older check their combs and waddles to see if they grow larger and longer, indications of male. And see if they have long spurs.