From experience I know that the problem is not just what the deer will eat but, what will not clog your feeder. I have tried dry feed, split corn, corn and horse feed. The first thing I learned was, although my feeder had 150 lb. capacity, it clogged that way. It worked better if I filled it half way. If the humidity stayed high, that clogged it. During the dry times, whole corn worked the best. When not using feeder, they seemed to prefer the feed with molasses in it. Also, horse feed worked as weel as deer feed and was cheaper with higher protein. I usually bought 12% protein.
You have to watch your feeder to make sure it stays clear and working.