Appolo,
You could use a corn feeder pipe, sour mash, a cresote post, or sow in heat scent post.
Personnally I perfer the sow in heat and the cresote posts. For some reason the hogs love the smell of creosote and love to rub on it. The posts are very easy to make....useing jute or hemp rope roughly 1 inch thick wrap the rope around a post....(a tree will work as well).....from ground level up about two feet, securing with a hangmans knot. This way there are no ends for the pigs to play with. Pour cresote or sow i heat scent over the rope. We would set these up on the edge of cover and