Any one know if it's really common to have to seperate multiple male rats at sexual maturity. Or does it all depend on how long they've lived together and other circumstances? Because I was told there was A CHANCE I may have to seperate my boys. And I was just curious to how many of you with multiple male rats have had to do so.

No idea, though I wouldn't think so. My experience with other animals suggests that if they do have problems, getting them neutered should probably reduce the problem.