Dogs running free will sometimes chase chickens and horses sheep and whatnot because it's their nature. The people who own these animals may love them just as much as you love your dog. The best way to keep your dog safe is to keep it on your property. I told my neighbors I would kill their dogs if they ever got after anything of mine. They couldn't believe it. One day thier dog killed somebody else's animal down the other way. Cost my neighbors $20,000. So they chained the dog with a long chain. Just long enough that the dog could jump my fence, but not reach the ground. So the dog hung it self. It takes at least some brains to own an animal.