I also think they are dogs. If they are as far away from people as you say, then they are definitely up to no good. My guess is running deer. I have seen this many times. Even if someone has a good dog, all it takes is a little neglect (owners at work 8 hrs a day), and the dog gets bored and starts wandering. Pretty soon he has a group of friends, and then they do exactly what dogs do. They hunt/chase.