My cockerel is around 6+ months old. He's pretty good with the mating part of my 4 hens (lost one), but aggressive towards me and my teenaged son. My wife can pick him up and he does nothing, maybe growl a little but never any aggression. But me? Every morning when I let them out, he attacks. Sometimes I'll hold him down, other times just give him the brush off and stare him down. There's no really training this one at this age though. His memory only lasts a few hours. But when my wife is around, he's a perfect gentleman never attacking.
Saturday he was doing his thing and I had my gloves and so I picked him up. He must have bit my arm 20x but I was ready since I had a coat on. I held him for a long time and he started talking to the hens. No lie, he got one to attack me as well. I held him even longer after that and then held that hen. We plan on raising at least 5 more to give the others a break but for now they'll have to just endure him. Or if he gets worse maybe not. Holding them down doesn't always work especially at this age.