Pup had intention of eating it. I voiced displeasure and she seemed to loose most interest in the carcass. In the end, I am OK with her eating it so long as parts do not left in areas I do not want them.
Another predator could have been involved. Remains are on upper size range that a Great-horned Owl carry any distance in flight. My owls do hunt over closest neighbor, but I do not know if they hunt over next closest neighbors. A fox could be involved as my dogs have stolen their caches many times before. Fox option does not fit well because they usually cache kills relatively close to kill sight in my experience. Another dog could have packed bird a long ways and forced to drop it by my dogs.
Closest neighbor with chickens does not appear to have them any more. That is a change in the last month. I do not recall him having leghorns of any sort. The next closest neighbor that is more than 1/2 mile away and well beyond where my dogs go does have one White Leghorn hen, but he said she is present and in good shape at time of my visit this evening. Next closest neighbor with chickens I know of is a mile away. Will approach them tomorrow.