I'll offer yet different opinions. It's not surprising to me that we have different opinions. We all raise them differently with different goals, flock make-ups, management techniques, and different set-ups. So we will have different experiences and observations.
I grew up with a free ranging flock on a subsistence farm in Appalachia. We had a flock of one rooster and about 25 to 30 hens. We relied on broody hens to hatch and raise replacements. Other than gathering eggs we had little daily interaction with the flock. In good weather they'd feed themselves. If snow was on the ground we'd feed them corn. The flock, which scattered all over, was far enough from the house that we did not interact with them except when we were taking care of the cows, pigs, and horses. That was basically just to walk by them. The only human aggression I remember was when a broody hen thought someone was threatening her chicks.
I don't raise them that way. My goals are to raise them for meat and to play with genetics. I can't free range because of predators. I have three different coops/shelters to lock them up at night, a 12' x 32' main run, and an area about 45' x 60' in electric netting. My climate is such that they can be outside practically every day of the year. I overwinter one rooster and 6 to 8 hens, but I incubate about 20 chicks every February and raise them with the flock with my brooder in the coop. Then when hens go broody I let them hatch and raise another total of 25 or so chicks with the flock. In summer I may have over 50 chickens in this area, most of them growing to butcher age. I generally keep one cockerel to replace my rooster every year as my playing with genetics requires. I typically eat the rooster when the replacement cockerel is about 7 months old. The rest of the cockerels are butchered by 23 weeks. I butcher most of the pullets around 8 months, after I have decided which ones to keep as replacements. I interact a lot more with them since they are confined and I'm retired and spend a lot of time outside where I can and do observe them.
This is what I base my opinions on. Your set-up, management techniques, and goals are certainly different from mine. But at least you can see where I'm coming from.
The behavior and interactions of that immature cockerel are really familiar. Until he matures enough to dominate and be the flock master the others will resist any of his attempts to take over. Chickens are often bullies. Size doesn't matter, its the spirit of the individual. I'm kind of weird on here, I believe the females have a part to play in this process. Different females have different personalities so the interactions are not always the same. I also think the maturity levels of the females play a part. Social interaction is complicated, each group each year is different.
I've seen a 5 month old cockerel able to take over a flock of mature hens. I've seen most hens in the flock accept a cockerel but the dominant hen did not submit to him until he was 11 months old. If he tried to mate one of her flock she's knock him off. I've seen a 13 week old pullet submit to a 13 week old cockerel, none of the mature hens would. I've seen a lot in between. The best way I can describe it is dominance. Some males and some females want to dominate more than others. That can generate a lot of conflict, especially if they are housed in fairly tight conditions. Eventually, when they all mature, it tends to become a peaceful flock but it can be pretty wild getting there.
I don't know what your set-up looks like, how much room you have, or even your tolerances. I tend to let my cockerels, pullets, rooster, and hens work it out as log as no one is getting hurt. If someone is getting hurt I generally lock up the aggressors more than the victims but I base my actions on what I see. I don't know what your best course of action is. I could see locking him up, either alone or with some females, until he matures. That could be months.
On human aggression. Growing up that wasn't an issue. We did not handle them, try to make them pets, or interact with them that much. It is more of an issue now since mine are confined and we interact with them a lot more. I don't handle them that much or try to make them cuddly pets but I am around a lot more. Occasionally a cockerel will threaten me, usually flaring his hackle feathers and trying to intimidate me. He may even attack me, generally from behind. When this happens I walk him down. I face him and slowly move toward him. If he attacks, which is rare, I gently toss him back with my foot. I wear long pants, he wont hurt me. Most of the time he backs down and runs a short way back. I stand still for a minute to see what he does. If he goes about his business I move away, never turning my back. If he doesn't walk away or moves toward me when I try to move away I walk him down again. I keep doing that until he lets me walk away without threatening me. I may have to do this two or three times but generally they learn I'm not to be attacked. I've only had to eat one because he didn't learn. Others do this differently. I can think of one person on here that wears long pants and ignores them when they attack. He says they learn it's no use so they quit. Other may chase them down, pick them up and carry them, or hold them down and "peck" their head with their fingers. I'm not saying my way is the only way or the best way, just the way that I go about it. It doesn't always work but usually.
There is another part of this though. Occasionally I get one that learns to leave me alone but will attack other people. I've had them attack my wife if she went down there without me, she'd carry a broom. I've had a couple that would attack the chicken sitter when she fed and watered them. They can learn to leave certain people alone and not others. Most of mine don't do this but I've eaten a couple because of this.
From my experience you don't get guarantees with living animals and their behaviors. Each one has their own personality and even if raised under the same conditions can react differently. I don't know your goals or even why you want to keep a male around but that's your business. Hopefully you can get something out of this that might help you.
