I had used plastic barrels in the past- never again, the squirrels chewed through the top and bottom. What feed hadn't spilled out was ruined with mold by rain water running in the top.

I suggest a smaller metal drum (like a 30 gal roughly) and then I drill a hole at 6 and 12 on the barrel about 10" down from the top. Then run a plastic coated metal cable though each hole securing the ends with bolt type cable clamps on the inside. Wrap another section of cable around that cable and secure that with a clamp allowing enough room for the first cable to slide freely through the loopn so you can level it. Get a BIG pulley to A. Make sure it doesn't break due to the weight and B. makes it easier to hoist the 30 gal drum up in the air. I usually take a come-along with to ratchet my drum up and then secure it to a tree screw with a loop I tie into the end of the cable. A corn filled 50 gal drum would take a truck to hoist in the air that is why I recommend a 30 gallon approx size.