I have mixed 20% protein pellets available at your local feed store, but getting it to mix and distribute evenly is a problem. The pellets disintegrate quickly on the ground and are not very efficient. I imagine that is why the serious game ranches always put the protein pellets in a separate gravity feeder, while broadcasting the corn. Deer love sweet feed, but so does everything else from birds to fire ants. Being sticky, it does not work in feeders, but I will spread a little around when I visit the feeder and check the trail-cam. If you go out at the same (non-hunting) time of day, the critters will get used to your presence, even waiting in the brush a few yards away until you leave.
If you can afford it, year-round feeding is best, pushing the protein feed from January to August to promote fawn development. Corn is mostly cheap, tasty calories for deer and is most important in the fall and winter, Oct-Feb.
Whether you hunt over the feeders or not, they are an excellent method to evaluate the size and health of your local herd when place at an observation point or trail-cam.