If the dog has killed the chickens and he does not care, I would avoid trying to deal with him and just call animal control. A fine or the threat of the dog being taken away might be enough to fix the problem. If my dog killed someone's chicken, I would be horrified, even if that person was not attached emotionally to the chicken. That being said, when I was growing up, we had dogs that we could NOT keep contained. We tried everything. Eventually we had to have one put down because she was ill and we sent the other one to a dog rescue that takes animals and relocates them to a place where animal control cannot get them. They still tried to find her to put her down. It was awful. Our dogs were not vicious, just out of control. There was poor training, not enough exercise, hunting instincts that they rarely got to work out, and no human pack leader. They liked to catch cats in the neighborhood. I don't blame our neighbors for being upset. I do blame animal control for making it personal.