what age do roos crow?

[Henrietta23]

My buttercup/silkie roo crowed at 6 weeks. My two other chicks who are now 7 1/2 weeks and everyone swears they are roos, haven't even attempted a crow.
And I agree, Oliver's crow is hysterical! It sounds like he's trying and someone is trying to prevent him from doing it! It's not too loud yet which is good since he lives in my house still!!

 

[Vamp-A-Billy Princess]

Mine havent tried yet. Some of them started doing a new noise. Its sort of vibratey and sounds kind of like frog chirping. They've been doing it for 2 days now. Can chickens purr? Maybe they have been talking to the cats...