it's an easy answer, not nearly as hard as people seem to think. Do the Right Thing. that way there's no guilt later, and no way to get in trouble. tell the neighbors you found a chicken that had been attacked by a coyote, and assuming it was yours, you brought it home. now you realize it isn't yours, and if it IS theirs, would they mind if you used this as an opportunity to try to nurse it back to health? just stealing it is wrong, but also ignoring what you want is wrong too. i bet they'd be glad to have it treated.