Two things I can think of right away are that you may not be using the wind and if any deer are in a bedding area near you and are downwind of the cahances are that you will never see them! The second thing is that there may not be any bedding areas on the property and they are just passing through there during nighttime hours and that's why all your corn is gone. Getting in and out of an area properly that you hunt is as important, if not more so, than the way you actually hunt it.