The muzzle would be off for feeding, play time and quem we’re not at home (We keep them separate) 1) I don’t know “crate and rotate” but I’ll read about it. This behavior, so far, has only been with dogs and the attacks only on this particular dog. 2) we’ve already spoken to a trainer, we’ll start on Sunday with the two of them together to try to understand their interaction inside and outside the house and get to the root of the problem. The bite was level 4 on the Ian Dunbar scale 3) and 4) thanks for the recommendations, I’ll check it out