This has happened with us as well. Most of the time our girls
love each other. Play well, wrestle, and drink out of the same
water bowl at the same time. But on occasion they get into
death brawls. A ninety pound shepherd-akita-retriever mix versus
a 40 pound australian shepherd. It's awful for us. And we spend
about a week or two getting things back to normal, which is stressful.
It just seems like they get over e***d and then one of them
crosses some boundary and they go at each other.
We're not sure what to do. It has happened twice this year. And
it's hard for us not to be paranoid about putting them together