Before CM TV shows I had a Work Pack I was fortunate enough to have a huge fenced in property that the presents of dogs deterred thefts, most of the "bad dogs" that I got were introduced into work pack slowly over a week or so and YES there was a a few squabbles at first but it did not take long for the dogs to figure out that it was a pretty good place to live and they adjusted..the put down dog had no pack problems at all it flat out hated people even those who raised it from a pup and was like leaving a loaded gun on a lunch table at school..you always knew something bad would happen just not to who or when, trust me I tried with this dog, but it was hopeless..and I came to think you were right to much time spent on a hopeless case was keeping from saving good dogs.