That is so scary. Yes we are definitely getting more cameras. I was thinking that maybe she was shaking her head for the splattering to occur, but then I thought if there is severe pain she may not want to shake her head. Further I had thought chickens go into some weird trance at night when they sleep so I dismissed late night fighting, but perhaps they fought right after sunset when they went up into their enclosed area before going to sleep. Or the chicken was in its "trance" making it easier for the person to grab her and beat her over the head with a tool very easily and quickly. All speculation I guess. If I didn't have issues with the sitter/boyfriend I would just straight up assume it was chickens/rooster fighting.