At what age do roosters crow?

[RECE*2C*]

mine are 7 weeks and one of them crowed for the first time today but when he was a few weeks old he would honk it was funny

 

[grassoviso]

I have Brown Leghorns that are about 10 weeks old now. If any of them were to be Roo's, do you think they would have started crowing yet? I got them from TSC and were told they were all pullets. However, I have heard from others that they are not always.

 

[mtnbiker46]

I have a lovely large RIR and he's now 6mths old and hes started attacking me if I get close to him..he pecks my shoes hard now but still not crowing?
Can I confirm he's a roo?