We bought 2 guinea pig brothers in August, all has been seemingly well until Christmas Day,they started fighting, one ended up with a shredded ear! We have separated them, the dominant did seem to be happier but has this evening started bearing his teeth! He can’t get to the other brother as they are in separate cages. We have put them side by side because they were subdued when they were apart and seemed to need to know each other was there, now I’m not so sure? Anyone else had similar issues?