One of my ducks had a 1-1/2" gash on the top of her head, though she was not the most severely injured of my ducks. The most serious injury was the predator pulled one duck's upper bill away from her face so that she had a lot of bleeding and swelling in her sinuses and on her face. Neither of her eyes would open and she was mostly blind for the first week, but now seems to be able to see. Her bill is much more stable, now, according to the vet. Most of the matted blood is gone, now, ten days post attack.