Are you sure chickens don't learn? I saw one acting on Saturday Night Live the other night Lol.
Yeah I'd say my fathers were probably genetic. They looked like pure rc RIR but I know he mixed some of what he called back in the early '80s 'fighting banties' not sure what kind of bantam it was but it probably could explain why his reds were good broodies. I think he liked a mean rooster because they were free ranged.
I personally won't have it, not going to make my kids afraid to go outside. We had to stay clear of where they were and avoid the flock.
Of course they learn, but this trait we have been discussing is genetic. The darned things have a few screws loose, and we perpetuate it by breeding them.
I picked this up as a kid. I had a few along the way. I had a habit of keeping just one male, and that was a bad habit. That was before I knew any better.
It is not a breed thing. It is strain or line thing, and can become established quickly by tolerating it.
There is a misconception that they are better protectors etc. They are often the first to tuck and run when things go bad. Most of them (not all of them) like to get you when your back is turned LOL. They are not all of the same of course.
When I was a kid, I had no building skills so I did not have a gate to my pen. I had chicken wire nailed around a group of trees. I had to cross it, in and out. With one rooster I was never concerned going in. It was the coming out that was a problem. LOL. I knew to cross a little faster coming out than going in. Especially if I had shorts on. I put up with it because I did not know any better.
I had ducks (Pekins) at the time, and had the same problem but it was not spurs I was worried about. It was the bill. That darned thing would leave some nasty blood blisters on a pair of bare legs.
It is a wonder I ever kept an interest at all. It is not worth all of that.
Along the way I realized that it was genetic, and could be bred for or against.
I have kids to, and they help with the birds. One has birds of his own. Some little game bantams. They will not tolerate it either. They would be quick to say that "he has to go".