I have been having the same problem. Mr Young Roo, Mr. Peep is the son of Willy my first Roo. Mr. Peep from the time he was a baby was the leader of the flock. When he became a man, ( one of the other chicks also became a Roo), He was beating
up Big Red, (twice as big as him), only having stare downs with Willy. The next thing I knew Mr. Peep and Big Red were attacking Willy tearing out feathers on his head. at the time I didn't know 1/4 of his comb was ripped. Willy had a bad time with his wounds, he got infected with mites. I did all the treatments for all my chickens, pen and hutches. I had Willy in a hutch by him self to heal. I gave Big Red to my neighbor, he placed him in the pen with his young girls, about 30, went off to do chores, all was fine when he checked on him. He went away for about 2 hours, came back and checked on him again, HE WAS DEAD! It was 118 that day, he has netting over his pen that give filtered shade (I have lots of shade) the only thing we can figure out is the young girls chased him around until he dropped dead. I did see the girls chase birds out of the pen. Big Red was so handsome RIR, contest winner for sure.
Back to Mr. Peep, I put him in time out for 2 weeks, let him out, he is still picking on Willy, He is keeping him on one side of the pen. I am watching to see any signs of attack. What to do? Can I cure Mr. Peep?