This is another trick we used to use for hogs to continually visit a spot. It is a roll tube. It consists of a 4 foot section of PVC pipe with a screw cleanout on one end to fill it and a cap on the other. Attached to the cap in the center is a steel I bolt with a small quick link. The cap is attached to the pipe with a couple of screws so it can be removed if needed. Along the length of the pipe are 2 holes about 3/4 inch diameter and offset from each other. Any more holes than this will be too many. In the end of the pipe with the pipe cap is a small compartment made from a 1 pound Folgers coffee can cut in half and shoved down in the pipe to form a chamber. This chamber is filled with a handful of small smooth rocks and the pipe cap put on.
The whole thing is then attached to a small tree via a 3 foot steel cable attached at one end to the quick link and to the tree with a big loop around its base. You want to have enough room around the tree where the tube can be pushed all the way around the tree. There will be a 10 foot diameter bald spot on the ground where they push that tube around.
Fill the tube with shelled corn and pour some on top. The hogs will find the corn and eat what they can and figure out pretty soon if the roll that pipe corn will come out. They will send that tube around and around that tree. Here is the best part. After they get all the corn out, the gravel in that little chamber at the end will still rattle when they roll it and they will think there is still corn to get out. The little chamber of rocks will keep them around for several days after they eat all the corn.