We had this issue with a foster that we introduced into our group. We were originally going to keep the foster boy, but after working for a year, we finally gave him to a friend.
One of the reasons that the vet gave was that our "alpha", Piper, and the new one "Bentley" were trying to assert their dominance. Piper was, is, will always be the "alpha" in our place and at age 7 didn't like the new guy trying to assert his dominance.
He kept attacking her and I received a couple of good bites while trying to separate them.
We tried water bottles (spraying them) and cans with coins (shaking loadly) and the two would not separate. We even went to the point of the puppy "prozac" with him and he would still attack her.
We ended up at the vet three times and had to keep them separated constantly. Even when we were in the room he would sometimes just "snap" and go after her.
We initially tried to determine what the cause was (toys, treats, food dish, too much attention to one, etc..) but there were times that we took away all toys, no treats, bowls up, and they were on the floor across from each other (about 15 feet apart) just staring....he growled and took off after her.
I know that they are small, but they knocked over a lamp, pictures, etc...and sounded like little demonic monsters. Scared us to death!
You might want to try obedience training with BOTH of them taking them individually and then together...we tried it, but it didn't work for us, but could for you.
A lot of the time the "new" atmosphere is so overwhelming that they don't focus on each other.
Let us know how it turns out! Best of luck to you! |