I've had one of my roos. start crowing about 2 wks ago and he's 21 wks old. It is funny to hear them when they first start. He's a pro now. My other roos. didn't start crowing until he was 7 1/2 mos. old then only at night, softly until he got it down pat. I find if you have more than 1 roos. they crow more because they seem to compete with ea. other. Also I live out in the country and you can hear far, far away, roos. crowing and they all seem to want to answer ea. other and the challenge begins! Also, one of my roos. is very large also, and not only is it harder for him to breed but when he stands on the girls, he squishes them. One ended up very lame for several days, falling over, unable to walk, so I had to isolate her in the house until she was better. Sometimes "big" is not best for smaller hens. Be watchful. Sharon