About 20-25 years ago in Anza, California, a pack of dogs made up of town dogs, about 10 or 12 of them, used to roam at night, and congregate in the outskirts of town. They would go hunting in various fields, chasing cows, horses, and sheep. Sheep especially. Friend of mine warned the town that he had lost 7 sheep to these dogs over the course of about a week, with several so wounded he had to put them down. Warned them by letter to the editor of a local paper, I believe. Anyway, the dogs formed a pack one night, and he was ready. Shot and killed 3, wounded a couple more, then did the same as above, called the owners and told them where they could find their dogs. Not another word, and they got the message. No problem for him, and his sheep were safe after that.