I read the book about dog-on-dog aggression, which states it is a direct result of insufficient socialization. I have a lab/golden retriever mix, Cassie, that obeys all my commands and gets along great with almost all other dogs... the exception being my boyfriend's female husky, Sasha.
The past couple of months, they have been getting in fights and since Cassie nearly doubles Sasha's size, Sasha gets beat up pretty badly. The fights always begin when I'm not around (like when I let them outside to go potty and I wait in the house), but as soon as I run outside and pull Cassie off of Sasha, Cassie calms down immediately and Sasha just hides behind me, terrified. Cassie does not do this with my other lab or my boyfriend's male husky... actually, Sasha is the only other dog I have ever seen Cassie fight with. And Cassie only jumps on Sasha when I am not around or paying attention. I'm scared that they will get into a fight while I'm at work and Cassie will end up killing Sasha.
I have a large fenced-in back yard, which is where they normally spend their day. I have thought about leaving my two labs inside during the day and leaving the two huskies outside, but that would leave two large dogs restricted in the house with no where to get exercise or use the bathroom for 10+ hours a day (my boyfriend also has to work). I can't do that to them indefinitely!
I don't think they're fighting over dominance because, due to sheer size and fighting ability, Sasha is immediately down for the count as soon as a fight breaks out - she doesn't even try to fight back. She is scared to even go off the back porch unless I am out in the yard with her (it's like she wants to make sure I am right beside her or within ear-shot to protect her).
When we are home, we try keep them around us constantly to make sure they do not fight and we have taken away all toys and treats when we are not around (hoping to remove anything that they may be fighting over), but the situation is not getting better... it seems to be getting worse. We have to work and they have got to learn to co-exist without constantly fighting. What can I do? Any ideas? I'm willing to try almost anything at this point!!!