Squirrel Proofing?

I used 30 gallon fiberglass well tanks (remove the bladder). Never had a problem with squirrels chewing into it - or bears. Its not perfect, but there again I never put a lot of time into it. The rounded bottom made it difficult for the critters to get on the feeder, but there was always one.....you know the guy.

I like the metal Moultrie feeders myself and to squirrel proof them I put on the fish caster motor heads.
It one direction which keeps the hogs from digging out the legs of the feeder as well.

http://www.moultriefeeders.com/feedcaster-kit

Kilboars Hunt Club