Good question about why your Oscar flew out of yard instead of running back to his coop. I agree that due to age and inexperience, he could have panicked and flew away. But it still seems odd, unless Buffy was attacked Between Oscar and the coop, so he flew away from attack rather than try and run toward/around the predator. That issue Does make me question possibility of a ground predator. All other info u provided still makes me think hawk as culprit. Hopefully not a raccoon, coons are much harder to defend against. Please keep an eye out and let us know. Within a day or so u should see the culprit. If u have a game camera, put it up near the site where Buffy was attacked, and let the camera identify predator for u.