I have shot exactly two deer in the head. Both were deer that had already been shot, poorly, by others and trailed to where I found them. Both, interestingly, laying in water holes. Both shot with a rifle with open sights that I use for up-close(50 yards or less) hunting. I don’t shoot deer that I’m hunting in the head. Those heads just move too much and if I’m pulling the trigger I want it coming home with me.
On the other hand, I shoot hogs in the head(or more often the head/neck joint) all the time. But aside from the constant movement, hogs don’t exhibit the frequent up/down movement by a couple feet that deer do. It’s several inches at most with a larger target area.