RE: what happens to all the deer
With hunting presure, deer sometimes move more at night. Sometimes they just become alot more wary and harder to hunt later in the season. Your best bet is to try to hunt over some sort of food source later in the season. When the weather gets cold, the deer will have to move to feed. Also trying to hunt some in the middle of the day. Deer will feed during the noon hours to conserve energy especially when the weather is cold. They feed at the warmest part of the day in the dead of winter.
Good luck!