A hog oiler is a mechanical device employed on farms to be used by hogs to provide relief from insects and offer skin protection. It consists of a reservoir to hold oil, and a means to distribute the oil onto the hog, often via grooved wheels or cylinders. Hogs seeking relief rub up against a wheel (or cylinder) causing it to rotate and dispense oil onto their bodies.
Like many vintage farm implements, hog oilers have a loyal following of collectors. Prices paid by collectors can vary widely, based on size, functions, and condition of the machine. Smaller hog oilers can be purchased for sometimes thirty dollars or less, while the rarest models have asking prices in the thousands. The majority of hog oiler finds today are in "hog belt" of the upper midwest United States.