Let me first set the scene. I have 8 dogs of my own: Charles (border collie/chow 12 years), Roxie (Pom 9 years), Max (Pom 9 years), Sadie (yellow lab/husky 6 years), Joe (aussie/chow 5 years), Moe (cocker spaniel 5 years), Buddy (cocker spaniel 2 years) and Suess (Spaniel mix, 1-2 years). These dogs are inside/outside with a doggie door to a fenced yard.
I also foster for the local humane society - right now I have 5 dogs in kennels outside, with shelter.
My problem is that Sadie has attacked Max 3 times in the last month, always getting him by the neck and not letting go. She has broken the skin all 3 times, but nothing else. Sadie is approximately 65 lbs and Max is 15 lbs. All 3 times were when the "pack" got into an excited state - once when my husband came home, once when I was feeding the foster dogs, and once when I came home. I have been keeping Sadie crated unless I can be in the room with her and make sure I'm there in case the "pack" starts to escalate and then I step in and put her in the crate. I also crate her when I know the pack will get excited.
I've read the some previous postings concerning the alpha, but am curious if that will work in this situation since it seems Sadie is snapping into some kind of instinct when the pack gets excited. She and Max get along fine whenever the pack is calm.
I would appreciate any advice. Sadie just showed up on our front porch about 4 years ago when she was about 2 years old. We've had Max since he was a puppy, 9 years ago. They are both very special parts of our family.