New to the world of chickens. I have seven chicks that are 6 1/2 weeks old. I suspect that two may be roosters, but I wanted to get the opinions of the experts. The first suspect is a black australorp. Big pink comb. Could that be a tell tale sign? Suspect number two, a black silkie. How do you tell if these are roosters? Notice that the black silkie is quite a bit larger than the white silkie, and it also has a "feather hat." Any guesses are greatly appreciated. Thanks.