Nice little AI you got there.
Animals seem to turn or move at the last second every time i try to shoot their head for the bonus damage. Every time i power shot they either do an animation that move their head out of the way (eat something on the ground or lay down) Or they seem to turn around the last second and i watch the arrow sail past their head.
I’ve even sat there waiting with the arrow drawn. Wait for them to be done with an animation and then fire and yet without fail they do something that dodges the arrow. I end up having to aim for center of mass and not bother going for the headshot bonus. You make that perk really useless.