I have these 5 young roosters (13 weeks). I am newer to this, so I don't know if they're being mean or if it's par for the course. They are destined for the freezer. They jump on the smaller ones constantly, who they've grown up with. I've also tried to introduce a few chickens about their age and they just jump on them instantly and it tends to be more than one and the others will join in. it seems to be these 5 that are the problem, I have a few other roos that will peck a bit and go their own way, but aren't so aggressive, not jump right on them. I'm just wondering if it'd be better for all parties to separate them for the time being? I have some 7 week olds coming up also and I wouldn't dare put them out with these guys!
Definitely separate them from your flock. They should be on a higher protein feed anyway, 23%, with less calcium than you'd give a layer flock. http://scialert.net/fulltext/?doi=ajpsaj.2010.53.59