We picked our 7 chickens from a mixed bunch, some hens, some roosters, some young looking chickens. We didn't know what breeds or how old they were. I did some googling and figured this was a standard Cochin and fully grown. then she started mounting other hens and her comb and wattles started to grow. But the tail still looks the same and she or he gets along with the other rooster. So I guess this is a rooster?