Quote: Not in my experience. What causes his aggression is his breeding, generally speaking. A rooster who has attacked a human, who is then caged and continued to be bred, will often produce offspring with a high incidence of aggression towards humans. If you keep breeding that on, the trait gets stronger and stronger. Then you end up with males who will likely attack whether or not they've been handled, simply because the ancestral imprint is so strong.
I breed for tameness among other traits and have never had a male of my breeding attack me, and I've had hundreds of males who freerange together around the houseyard and farm, in a mixed flock. In my experience if you breed a bully you get a bully, so I don't breed bullies or aggressive roosters. I handle all mine from hatching onwards. Not excessively, but enough to be able to spot and weed out those which don't have any leaning towards tolerance for humans. If he or she won't tame, he or she won't breed. Breeding only those which will tame has worked very well for me. A chicken which prefers to avoid humans and won't allow itself to be handled peacefully is just trouble in the making, and very likely to breed trouble in turn. Not breeding those sorts means you end up with birds which take well to handling from a very young age, and this makes everything else easier.... Treatment and transporting and so forth.
Personally, I handle all my birds from hatching onwards and out of many hundreds of birds I've have only had one male attack me (a male I didn't breed, which I bought in from elsewhere --- the breeder kept animals that attack people, which should have been warning enough for me, but wasn't at the time because I thought it would breed out quickly enough).
Being tame doesn't make a good male more likely to attack but might make a bad male more likely to attack, I'd guess.
Quote: I think you're right. I do believe aggression to humans is something which is either inherent or not present in the bird to begin with, not a trait they suddenly develop; good males don't turn bad but bad males will act on it sooner or later... And they don't turn good afterwards. I don't rely on fear to get a male to respect me, since I've found tameness and trust to be far more effective.
In my experience there are 'gateway' mentalities and behaviors which if unchecked can develop into aggression to humans generations after they first show up in an animal's family tree. The same is true of other negative behaviors. Often just a hint shows up in the ancestor and if you don't know what that warning sign is, it can emerge with seeming suddenness down the track. But the warning signs were always there, progressing with each generation.
Aggression to humans has always been linked to other bad social traits in the birds I've seen it in. Now I'm more experienced I can spot the warning signs in very young birds, and it's never been something that goes away or is grown out of.
So far I have never seen aggression to humans in a bird which was a "10 out of 10" in any other area. It's linked to a whole mentality (or instinct blueprint if you prefer) which is aberrant. And thankfully it also seems to be linked to bad genetics; no bird I've culled for aberrant behavior has been a genetic loss.
I think that human-aggressive birds are the result of those breeders who keep a male who attacks humans, and probably inbreed excessively too, fixing the negative trait deeply. Sometimes desperate breeders of purebreds will also keep an aggressive male despite his attacks, just because it's a rare breed, or just because his physical type is what they're after. Some other folks believe it's natural to any male to be automatically and indiscriminately violent, despite the evidence that it's not natural nor normal for many, so that's what they breed on. This isn't meant to be a slur on anyone. We all believe different things. But it has been my experience with all the bad males I've bought that they are a direct reflection on whoever bred the last five or so generations of that strain or family line. I've been told by the likes of such folk that "inbreeding only matters with mammals".