[Oddsock]

Walks together, really helps bond dogs. So along with training, walk them together. With help if possible. Distract them from each other with commands, like sit and down. Do they like treats?

Decide who you deem is top dog, then always let that one have the treat first, get picked up first,... etc and stick to it. Swapping around confuses them, when they are rivals.

There is no quick fix. Letting a good trainer come to your home, can help. They may see what cues you maybe giving when talking, feeding, interacting with the dogs, that you are giving without realising it. Do they fight when you stroke one or other? Do you let them on the bed?.

Personally I hate muzzles, they can make a situation worse. Yet have had a situation in the past, when we had to use one on a GS that ate rocks, when on walks.

How old are they? Do they draw blood from each other? What have you tried so far?

Hope you can sort this, please keep us updated.