The purpose is to get hog to hang longer at certain areas on the lease and keep occupied. I know alot use the pig pipe but I prefer the barrels. The barrels give you an idea the size of the hog, are sturdier and can hold more bait for those that don't get to the lease as often. I have a slinger/timed feeder at each plot or area I have a stand, then associate a roll barrel and a rubbing post close by all targetable from the shooting tower. Just make sure it is far enough away not to get tangled on the legs. I use heavy chain or wire rope to connect the barrels to a ground anchor (long ones w the plate at the bottom)or 2 cinder blocks. I have 2 size barrels I like the free ones are from a car wash (held soap) and are 15 gallon and refillable through a bunghole, the others are 55 gallon plastic barrels with screw on tops $22. Only dry corn, corn on the cob dry or dry dog food or all 3 are the bait. 40-50-75 pounds of bait, what ever you can afford. OK, everything is extra heavy duty, they will break things and your barrel will be 100yds or more away from where you put it. Get your barrel and install a hard point, on the large barrels I do this on the opposite end from the top, use a eyebolt with a washer on the outside and inside and double nut and use loctite. I start with 2 or 3 9/16 holes(cause I am cheap) drilled into the barrel high low and middle opposite sides. Hardware: Heavy duty, hogs break things! Every time you transition from the eyebolt to the chain to the cinder block install swivels. I use 7-10' lengths of chain or wire rope, the area needs to be flat and clear of things that can tangle it, so you can play w how long you want this. Oh my small barrels the have a handle I knock out then use a clevis bolt to replace for the hard point. If you sue snaps or clips use the kind that pull out not push in, typically I wrap w duck tape and the hog can and will open these. I have cam pics of hogs beating these to death for hours, the laying down beside them to rest and going after it again. If the holes are too many or too large they will empty a barrel overnight so experiment with them, the 9/16 and 2 holes is good, 3 gives a little more corn. 2 holes and they are good for a week or 2 and if you put dry cob corn it lasts even longer. The dog food should be the large kibbles and as stinky as possible. When you are first starting toss some corn around the barrel to get them started, they learn quickly.