I draw the line at if I cannot trust them not to maim or kill without supervision, they have to go. I've had a variety of breeds. I had a male Pit that would let orphan kittens nurse on him. I've only had to get rid of 2. A Huskey I was given, gorgeous and smart. Killed chickens every chance she got. I tried for months to correct the habit. I returned her to her prior owner. The other was a Rottweiler. I purchased her from a breeder i knew personally. He bred K9's and other defense dogs. Great lines, I knew both the Mother and Father. Belle was vicious from the get go. Not to your face, just demure and obedient as could be. As soon as anyone turned their back, she attacked. No idea why. She was returned to the breeder to see if he could do anything for her, after 2 months he offered a refund. I'm pretty sure he euthanized her.