Looking for some advice for a poorly male guineapig. He is 3 and lives with another male (has done since babies) I’ve noticed he has gone really thin and only eating fresh food. Took him to vets today who can’t see anything wrong, but said it could be his back teeth (which she couldn’t view easily without sedation) so he’s on metacam and recovery feeding by syringe and I have to monitor his weight. He is pooing normally. For the first time this afternoon I’ve noticed he seems to have a ‘substance’ dried on his fur on his back end. Don’t think it’s poo, and his cage companion who is the more dominant and larger also looks to have something wet that has dried on his fur. (Around the back end) I have noticed the larger one recently try to mount the smaller one - could this be a stress related illness with the larger one trying to mount him? I have had them 3 years but had females before so not terribly experienced with males. We have a third that bullied so he now has to live in a cage next door! Thanks in advance for any advice you can offer.