I too have a tempermental Chin, his name is Sid. I've had him for two years and he's always adored me and vice versa. But, about 2 months ago I bought another young ebony, also male. I introduced them slowly, using all the tips I could find and after the first month they seemed fine together at playtime. But, now the progress seems to have gone backwards. They can't be in a cage together for more than 20 min. without Sid getting very fiesty and begging to be left alone. Also, when they're out running around together Sid will get very territorial after about an hour. He charges, he bites (very hard) and he growls at me. His behavior scared me at first because I had never seen him act that way. I now have both of them secluded from one another because Sid's behavior is so violent and unpredictable. What do I do? Do I start again from the beginning, try to re-introduce them? Or are some chins just incompatible?