I'm so upset. My GSD was in the back with me and my neighbour was dogsitting another neighbours chihuahua. Hunter saw it and took off like a shot. We don't have fencing between about 5 houses and the dog was in a sort of "no mans land" that's city property but runs behind all our houses. He's always hated that little dog and had I known he was out there would never have taken him outside. I'm just sick over it. I truly believe my dog saw the other as a rabbit. He's always barking at them, coyotes and deer in the back. He's never been aggressive with people One bite and it was over.