You will need to hang your feeders high enough that deer won't be able to reach them or they will. Off of the top of my head I'd say at least 8 feet unless you have a varmint cage around it. Deer will stand on their hind legs to get what they want from the feeder.

The other problem we had was with raccoons. We finally defeated them with large diameter varmint cages. When we used smaller cages the raccoons would just reach through and spin the corn out. They got the best of us for quite some time.