If it makes you feel any better I had to separate my two chins a week ago. Kulu was getting his hair pulled out in enormous clumps and there was hair clung to the shelves. The incidents became more frequent and more severe so now I put a divider in the cage before there might be any bloodshed. It totally ruined my ideal chinchilla setup. I hope that maybe a year from now, when Spot gets older and calmer, I can try again. Mine can play together under supervision but they can't spend a night without someone's hair getting pulled.