Late development of human aggressiveness is a function of husbandry / environment. Something is going on with interactions between humans and birds that is promoting this.
Okay, maybe everyone can help me with this rooster problem (16 months old).
This is a double-copy frizzle (commonly known as a frazzle) bantam Cochin. The two copies of the frizzle gene seem to make them a bit more flighty. He always was and continues to be a hyper little rooster. I'm not happy with his rapist rooster tendencies and might separate him from the flock for at least the hot summer months (I'm in south central Texas). Because of his poor-quality feathers (from the two copies of the frizzle gene), he spent nights and cold days in my house last winter. He has been free ranging with my small group of mostly Silkie hens and another Silkie rooster the same age. Until I separated him from the flock because of the cold, he had been the higher ranking male, but ow he is subordinate.
I recently hatched my first chicks under two broody hens. I brought one broody and her 7 chicks from the LF flock that free range in the front yard into a little coop and pen in my back yard where the "little" chickens free range. Five days after my first chicks hatched, the Silkie in the backyard group hatched a solitary chick. A couple of days after the chick hatched, I put her in a separate pen and coop next to the first group of chicks and broody.
The back yard chickens, including the young roosters, are fascinated by the chicks. I am quite sure the presence of the chicks has increased the stresses the flock feels, especially the roosters. There has been no aggression shown between any of the flock and the broody hens or chicks.
However, my little Cochin rooster has taken to flying across the yard, squaring off with my feet and posturing like a frighting rooster. He started this a month or two ago with my adult son, who responded by kicking him when he attacked. Then he started the same behavior with me. At first I tried to think maybe if I treated him the same way as another fighting rooster would, which I believe would be to hold him on the ground by his hackles/comb, he would learn I was a higher ranking "rooster" than he is and defer to me the way he defers to the Silkie.
Then I read a long post by Centrachid. I believe one of the more important take-away points of Centrachid's posts is that aggression to people is a management problem. I've tried to deescalate the interactions with both problematic roosters and there is improvement. I still plan to cull the LF Ameraucana. The Cochin doesn't pose the same risk to people that the Ameraucana does, so I am trying to work him through the issues.
I took Centrachid's advice and simply stop moving when he flares at me. As his hackles start to relax, I move a bit forward. If he moves off, I move forward into his space. There are mixed responses, sometimes if I move into his space, he retreats while other times he flares up again. I am trying to get my son on board with this approach.
Thoughts please.