Aggressive Mixed Puppy
I currently have a 10 month old mixed dog who we suspect has some Retriever, Shepherd and Chow Chow in him.
We got him from a family's friend's friend when he was 7 months old because they just didn't have enough time to care for him.
We don't know much of anything before that, but it is likely that he was from a puppy mill/backyard breeder. He was already neutered before we got him and the past owners never mentioned any problems, though we never asked.
We had a few problems with him: leash-pulling and mouthing, but we have already fixed that.
And, in the beginning, he was fine with other dogs, except for the small dogs. He would and still does bully smaller dogs.
But now, he seems to also like to bully and attack dogs his size, not just the small ones, and only calms down around dogs that are bigger and stronger than him. We have to be extremely careful when we see another dog when we are walking him and keep a tight leash just in case.
As there was one time, where I stood to the side and moved way out of the path for a little dog and the owner to pass, when my dog's leash suddenly snapped and my dog raced for the little dog and pushed him over biting him and going for the throat. I pulled him back and apologized greatly to the owner and I carried him home, since the leash had apparently completely snapped.
We used to go to dog parks too just so he can meet dogs bigger than him that can calm him down, but we just simply don't really trust him around other dogs anymore.
I guess I'm looking for advice.
We did go to a dog trainer for his leash training, mouthing and his food aggression, but the dog trainer can't seem to fix or give us any working ideas for his aggression.
He is perfectly fine with humans but he just snaps when he sees other dogs his size or smaller.