A Hawk likely, Sounds to me, just happened to be full or get scared off before he finished the legs. The hawk attacks I have witnessed or verified over the years shows usually three or four [piles of feathers in a trail and the remains at the last spot. Usually given ample time the hawk leaves only the wings and the feet sometimes the wings still connected by a flap of skin and a pile of feathers. If they get scared off the bones left will be clean as a whistle on the legs or the thighs if they left it behind. The breast ifn still present will have large bits neatly sheared or pulled off They sometimes will partially eat the bird and fly away with the carcass minus parts including wings detached and left behind. Their dining area is remarkably clean of blood and soft tissues, etc. they are fast and effective butchers and remove large strips of meat or severe parts like pruners. Dry feathers and the stub of the wings with little left but the bone and feathers is typical. A mink usually eats their favorite internal organs first after killing the animal with a bite to the neck, they love the heart, liver. Often, minks will kill many more than the one they feed on and only partially consume much of the carcass. Fox usually drag their victims off to nearby perceived cover, before feeding, behind a fence row, tall grass or tree or whatever. Partially feeds and takes to den a choice portion or the entire carcass or invites nearby kits to eat at site. The dining site is usually "messy' as compared to hawks. Parts of the carcass may be strewn across the area and fox signs may be present, scat or tracks nearby. A good dog will take a scent on the trail of a raccoon or opossum and they have their own clues they leave. Good luck. I only let my bachelor flocks free range due to hawks and other threats here. I don't mind so much a donation to needy Raptors or a young fox family of my excess roosters. Though that may become excessive, even for me to tolerate at times and I lock them down in a secure run.
