Looks to me like you have a couple of boys. The first picture the red in the front and the white in the front. They were already getting bigger combs then the others. But if the white is Leghorn the females get really hugh combs too. If you post another pic at this age I would be able to tell for sure. With my chicks I can usually tell by 3 weeks by the comb. Also the boys will be getting thicker legs and at 5 weeks will be ddeveloping their wattles.