I need help with my Aggressive Mutt!!
I have a border collie, blue heeler mutt. I adopted him at 4 months old as a rescued stray. Now he is 55 pounds and almost 5. He is great in all respects except one: He has become extremely dog aggressive in certain settings lately. We can go to the dog park, be out off leash in the mountains and come across other dogs in passing and he is fine. But starting about 1.5 years ago he has become aggressive when there is a leash involved, if there is a dog that is really friendly and all on his face licking, if there is a toy, treat or food involved... The list feels like it goes on. When he is in the house around his bed, or what he see's as "his" room, if another dog comes up to me when he is sitting by me. And it's only towards dogs, you could take his treats away, his food, his bed, a toy, and as long as it's a person, he doesn't do anything at all. But his dog aggression is really becoming a problem.
A group of us rented a ski condo together in colorado this winter and there is another dog. They are TOTALLY fine together when they are outside walking or playing, they were even fine in the house together until last night when everyone was there and the other dog tried to come into the room where mine was sleeping with my boyfriend. They got into it pretty bad, and now everyone, myself included (and I am 5,000 miles away in Alaska) is stressed out. PLEASE HELP!! How do I break this behaviour?!
We used to have a roomate who had another dog and he was mostly fine (occassional scuffles over dropped food). Now he seems to be getting worse and worse. I don't trust him around other dogs anymore. He would have attacked a 3 month old puppy the other day that came up to play with him when he was standing next to me if I had not grabbed him at the last second. I work out of town 2 weeks at a time, could that have something to do with it?
He stays with my mom or my boyfriend when I'm gone and loves both of them. This is getting really scary and coming between me and friends... What should I do?