Corn isn't going to hurt the deer.
You can also usually have some fun gathering acorns. We used to have a few spots where we could fill up literally half a dozen big trash cans with acorns. Deer love them.
Deer will also eat bread. In fact, they LOOOVE bread. If you have a local bakery you can usually get the stale bread when they toss it.
They will also go through apples like crack cocaine. If you know anyone who has an apple orchard you can usually get the soft apples that they can't sell for nothing. You just have to pick them up.
Deer are browsers, much like goats. They will eat ALMOST anything in a pinch, but they do tend to relish certain items.
