I adopted a german shepard male about a year ago from an abusive home. We've had our struggles with him being fearful of various events and people but started working with him and we've got most of those types of issues taken care of.
Last night we had an incident. I had another dog previous to this new guy coming into our house. They occasionally get into disputes but normally they end quickly. Last night was a whole other situation. We keep their food in our pantry and I've noticed lately that the shepard has become territorial of the door. I've made him sit and backed him out of the kitchen several times until his food is in his bowl. I wasn't quick enough last night and a fight broke out. He had my other dog by the neck and was shaking him violently. I honestly thought he was going to kill my other dog. I could not get them apart. Finally, I had to just bite the bullet and realize that I might get bit to get them apart. Thankfully, I didn't but the whole ordeal has left me very shaken. My instant reaction was that this dog needs to go. He's a big lover and has never had that kind of reaction to humans only to Cooper (the other dog).
I've had dogs all my life and have never dealt with this kind of situation. I'm at a complete loss as to what to do