I had a pair of rude roosters that ended up living here (long story). They would attack people. We fixed that by keeping a snow shovel or broom by the back porch for self-defense. After a few weeks of "be respectful of personal space=eat food vs attack=get walloped across the yard" they fell in line and actually became somewhat friendly. I had no interest in socializing them, but my ex would
feed them Cap't Crunch and attributes their conversion from the mean side to that.
I would worry more about him being by himself, and how happy he would be. After we lost Cock of the Walk to a dog attack, Bungholio (the survivor) definitely latched on to us a bit more. He didn't seem too depressed but after awhile started to hang with the donkey. If your rooster doesn't walk the line after some, uh, "discipline" and seems unhappy or depressed by himself, then it's probably time to seek alternative arrangements for him.
Once I figure out how to post pics I'll try and upload the ones of Bungholio riding around on the donkey. Animals are weird.