Tino’s such a pretty boy. The Light Brahma in my profile pic turned into a mega jerk at 16 weeks. We’d heard LBs were docile, but he was turning out scary, not to mention he’s scary big. When he started pecking me and drawing blood on the pullets, we scrambled to create a modified bachelor pad situation. For 10 weeks, he slept in a 4x4’ cabin alone but spent days in the yard with his flock. This past week, he moved back into the big coop. Cooler weather, laying pullets, and a little more age have mellowed him for now.
Culling would’ve been a lot less work, but I wanted to at least try working with him. Besides giving him space to cool down, I needed to re-train myself, so I read a bunch of rooster articles. Most say to act like a chicken...or
not act like a chicken. That’s confusing, but there's a lot of good advice out there either way. I tried what made sense to me and watched to see if it helped his behavior for better or worse over days or weeks.
At first I worried that being kept alone at night would cause him stress, but he thrived. One thing I hadn’t realized was that he had been too wound up to eat in front of the pullets. With time alone at the feeder (I keep food and water in his cabin for him) he immediately put on weight, and that seemed to help, too.
Treats are a powerful tool. Over the summer, I'd grab a blueberry off the bush outside their yard and hand it to him the moment I walked through the gate. That worked wonders because it trained him to run up for good instead of running up to cause mayhem.
Overall, I always try to stay calm. That's definitely easier if you can remember he’s doing his very best to be a good bird. His entire reason for living is to protect his flock, but he’s just a baby and just a bird and may misunderstand what a threat looks like.
These days I can literally say, “No!” as he starts to run towards me, and he stops. I didn't know chickens could respond to verbal commands! So I do believe chickens are trainable. However, a few of the rooster articles say you can never truly trust a rooster, and I agree with that, too. I don't really think you can trust any animal fully, honestly.
Additionally, I like letting guests choose whether or not they encounter chickens. Even the sweet hens can be bossy. Especially Brahmas. They want to hang out alllll the time. Not everyone is down with that.
If a bio-safe visitor wants to go in the chicken yard, I keep an eye on the cockerel or simply pick him up and carry him around, or I'll put him in his cabin for a few minutes with treats. He’s never gone after anyone but me, but why chance it?
This is just my experience, but I thought I’d share in case it helps. Best of luck! Here’s what our boy looks like now. He's the hardest working cockerel in the biz: tidbitting, dressing up nesting boxes, and keeping an eye on the sky, all while causing a minimum of chaos compared to before
Roosters are crazy, but they rock.
I was talking to Little Gray (yes, I talk to my chickens) and she ran up behind be and started pecking and tugging on my shirt, when I turned around, she gave me an innocent look, and said: Bawk? Sure enough, they needed a water refill. She is my favorite chicken haha, I like her better than Tino for sure. Funny thing is 8 week old Little Gray is bigger than her.
But I assure you mine KNOW they aren't allowed on the kitchen counters and if they decide to hop up anyhow, they know it better not happen in front of me or my DH 
I'd guess that- like most things- a big part has to do with the amount of effort you are willing to put in it and how much it means to you-- and even then, there are no guarantees...
