I purchased 3 RIR, 1 Buff Ophington, 1 Barred Rock, and 2 Red Comets (I think was the name of the last). They were all supposed to be hens but we discovered the Barred Rock was a Roo when he crowed. They are about 4 months old. Is there a way to know for sure if the others are Roo's too? The combs look short on the others.