Are my Hens, roosters?

[ericnash]

I am worried that 4 of my 6, 8 week old chicks are roosters. I asked and payed for pullets, but the comb and wattles on 4 of the chicks are MUCH larger than that of the other two. Is it too early to tell? Do they start crowing soon?

 

[Happy Chooks]

By 8 weeks, most breeds are pretty easy to tell. What breeds do you have? Do you have a picture?