I have to agree with Cindy, Serama roos seem to have a Nepolian complex, my Standard, bantam cochin roos, marans roos and leghorn roos will all share the yard and after one blow up they seem to decide who is boss and go on about the business of scratching and pecking, put one little serama roo in there and he's gotta conquer the world lol~ They (serama roos) need space and will rarely even get along with roos they are raised with.... maybe you can split your run and coop so each pair has half the space? Good luck with them and whatever you decide to do!!