Be sure your chicken wire covers completely. They are tricky. We ended up with the shotgun solution, after I went in the henhouse and the fat raccoon was on top of the divider wall. By then, he had already gotten nearly a third of the flock, and thought there was a red and white bucket on top of the henhouse just for him. He was getting in just below the rafters,an area I thought would have been too small.
The one we had would leave feet and a pile of feathers. If it turns out to be dogs, some of the dog tag money (in NY anyway) goes to replacing predation.