The case is now solved. We found two of the four chickens carcass' just behind the dog run, and two feather piles further up into the woods today. It appears that our dogs (Irish Setter and a very large poodle) have been biding their time all summer, and the chickens ranging just out of their reach finally got to be too much for them. My husband spent the better part of today fortifying the fence in the spots where it was breached. I read in another post where one farmer tied the remains of a kill around the dog's neck and made him live with it for a day to stop the bugger from killing any more of his chickens. I'm afraid that it would just be a prize for either of these rotten mutts. Thank you all for your posts - at least I know we don't have a "wild" predator to find. Anyone want a dog?