All three are doing this at 9 weeks of age? Somehow I get the feeling we're not getting the whole story, it just doesn't sound right. It's not that unusual for one cockerel to hit puberty pretty early though nine weeks is pretty early. For all three to hit puberty that early sounds strange. To me 12 weeks is early for all three but not unheard of. I'm wondering how old the hens are to put up with this behavior. This would be a fun one to see what is going on. It could be one of those things that makes chicken TV better than anything on cable, antenna, or satellite.
The explanation is that puberty has hit. Their hormones are telling them to dominate the flock. At that age it isn't about fertilizing eggs, it's about dominance. When the hormones hit the boys will often fight among themselves to determine which is most dominant. They don't always fight but they often do. They want to mate the girls. In chicken mating the one on the bottom is being dominated by the one on top, either willingly or by force. Usually with young cockerels it is by force, because no self-respecting pullet or hen considers them worthy to do it willingly. It just feels really strange to be writing this about three 9-week-old cockerels. They should be in their teens at least.
Often you read on here about hens schooling young cockerels, how some people think that makes a cockerel grow up with better manners if they grow up with a flock. Doesn't sound like that is what is happening here. It often doesn't in my flock either.
I don't know what your plans are for those three boys or if this behavior is bothering you. But that is not your question. As far as I'm concerned if no one is getting hurt no one is getting hurt. But it's your goals that count and you are the one watching them. Good luck!
