Male rats, if they are socialized within the male group, even when they rotate out to breed, are generally accepted right back into their core social group. Rats know which rat goes where in that social order and as long as everyone fits their place there is rarely a problem. You'll get the occasional rat that is picked on constantly or is a bully but generally there's nothing more than a bit of scuffling or boxing which is totally normal for social creatures like rats to do.

All our adults know that if they get nasty tempered I'll holler and sharply rap their enclosure. This teaches them early on I guess that I'm boss rat and they will break up any fight and run to cuddle each other if I do that LOL. I swear they likely mumble about me after I leave like a bunch of teenage boys that got caught being too rough...."geeze she's mean! we were just goofing around! geeze!"

Also to be honest, if I have a rat that beats up on other rats badly or is nasty with me, I cull it. Feeders or not, I'm not into breeding nasty tempered animals.