I'm also having some trouble introducing my male chins. Apollo is about a year and a half years old and Loki is about 4 months old (I've had him for about a month). I kept them isolated for about a week or so to let Loki get used to us but now they live in the same room, the cages are a couple of feet away from each other. For the first week or so I would let them out one at a time during playtime to sniff at each other through the cage bars, and for the last two weeks I have let them out to play together. It seemed like they were making progress but lately things are starting to slide downhill again. I thought Apollo would be the trouble chinchilla, but Loki is actually the one to instigate the fights or spaz out if Apollo approaches him. Yesterday Apollo appeared to be grooming Loki's backside (nibbling at the fur without pulling it out) which Loki tolerated for about 30 seconds and then turned around and repaid him by taking out a chuck of Apollo's fur
They've been in each other's cages and know each other's scent I'm sure. A lot of the time they ignore each other but I haven't seen any friendly behaviors yet. We've tried time-outs in their own cages (a little tricky sometimes since Loki is very fast and hard to catch) and distractions like the dust bath which worked very temporarily. Apollo's poor little butt is starting to look a bit patchy, but there haven't been any injuries yet. I think one part of the problem is that Apollo thinks Loki is a girl, I've seen him flirtatiously wiggle his tail and seems to be a bit amorous. We've tried doing the butt to butt technique as outlined here
http://www.chincare.com/HealthLifestyle/Introductions.htm while I held Loki and my husband held Apollo, but it just made them nervous and Apollo kept biting my hubby.
So I'm not sure what step two is. Should we keep going and keep exposing them to eachother, or should we separate them in different rooms for a couple of weeks to let them forget and then restart the introductions with something more like the cage within a cage technique over the course of 36 hours?
I know its possible they are just incompatible, but since it hasn't reached the point of actual hatred, attacking to kill yet I still have hope that we can get them into the same cage, I'm just not sure how to go about it.
Any advice would be appreciated.