I would put a camera up to see what is visiting the feeders and you may get a good idea of what was eating the piles of corn. When I have put out piles of corn I have had more coons, hogs, and crows visit the piles than deer. I grew some very fat coons and hogs. I finally started utilizing feeders and it took the deer a little while to start visiting. Take a look at a website that has some good products for you and email Mike he might have some good suggestions (www.mikeswildlifefeedersandsupplies.com)