My rooster just started to crow 3 months old. He has a good relationship with hens his age, and he decided to tell the world how wonderful he is. This is the time I introduce him to real adult hens. That usually shuts him up for a couple more months. (He is not alone, he is with 4 other rooster friends.) They have already made some friends from the older hens, sharing food trays etc. They are learning their place though.