Perspective from a Wildlife Biologist/hunter
Some facts from a biologist standpoint:
1. Most of bait that is put out falls to depredation of "non-target species". This means that a lot of what you are putting out is getting eaten by mice, squirrels, turkeys, coons, and possums. Therefore, just because you are seeing piles dissappear doesn't mean deer are the main culprits. It is truly surprising how much food small mammals can go through.
2. You are correct about the deer behavior. Especially in low food supply areas, more dominant deer will out compete the younger/smaller deer. The behavior you are seeing could definitely be coming from a big buck (or even a dominant, mean doe). Thing is, these deer could be hearing him walk through the leaves, get a whiff of his smell, etc...and this could mean he simply somewhere in the vacinity.
However, depending on the amount of coyotes and bobcats in the area, they could be sensing predators around them. Remember, when you make a food area that brings in small mammals/deer, you are making a food area for predators to concentrate on as well. And believe it or not, I've seen dominant bucks get spooked from an area by a single bobcat.
3. As a biologist, I have to say that even though it is legal to bait in several states it is not biologically sound. Keeping the piles small and scattered over a landscape can help keep disease down and "baitcasting" (speading corn with a sower or by hand over an area) can increase the number of deer seen (gives more area for multiple deer to feed at one time) while still lessening the chance of disease spread between your deer.
As a fellow hunter:
1. Try hunting all day long over these piles. Deer pattern us hunters just as well as we pattern them. Being there at an "odd" time can increase your chances of catching him off guard. Also, you will get a better idea of what is eating your corn.
2. Try not hunting right over the bait, instead make several piles a decent distance away from a bedding area and then hunt the travel route between the bedding area and the bait. Since many of your deer (large/old bucks included) move at dawn/dusk, you might not be able to catch them at the feeding sight but will catch them coming or going.
3. Depending on the food quality in your area you might want to try and do some winter wheat planting. It's easy to plant (just sow it out), requires basically no tending, and has a maturation date of often 45-60 days. Providing multiple types of food can drastically increase the deer visiting the area.
4. Try using scents and call depending on what you see in the area. If you are holding a decent bit of does, they will provide all the scent you need in the rut. Rattling, grunting, and using doe bleats can really bring a curious deer a little closer in.
Hope this helps and Good Luck!