I put an eye-bolt on the bottom of my barrel and chained it to a steel post driven in the ground. I punched holes in the sides that allowed corn to trickle out. In a very few nights, the barrel had been pushed round and round that post so many times it was a perfect clean circle.
It is fun to watch the hogs toss their heads to roll it and watch the little ones scramble. When it gets emptier, you can also hear it a long way off!
But I like Howie's hanging idea even better.
To attract hogs to a rubbing tree, we simply wrap rags soaked with used motor oil around a small tree. They start using them almost immediately.
pepaw