I have a roo and three hens. Yes, that is over-roo'd for the number of hens, but so far it's been working. One of the girls is missing some feathers on her back now, so I'm monitoring it closely.
I would like the option of replenishing my flock from within, should I need to. When I got chicken last March, at the beginning of the lockdown, I was trying to cover the possibilities. Yes, I got pandemic chickens, but I was planning to get them when I retired. I already have a big garden.
There are a lot of articles and threads about working with aggressive roos here on BYC. If you want to keep him, you can probably find some tips to tame him down a bit. I'm working with my roo, and he is showing improvement.
I was going at it as "I AM the boss of you, jerkwad!" But that wasn't working well. After reading about the subject and asking some questions, I've changed my tactics to "We are on the same side, buddy. But you MUST NOT challenge me. They are YOUR hens, but I am allowed to be in here and interact with them whenever I want."