Before antibiotics and vaccinations were available, hog oilers were popular implements on farms in the early 20th century. Hogs were kept in outdoor pens where they were exposed to all sorts of biting insects. Lice, mites and flies caused hair loss and sores on the pigs skin and could transmit various diseases. Coal-tar, kerosene, motor oil and even crude oil filled the tank of the oiler. Sometimes insecticides were added. It was believed that the oil would smother the biting insect pests. The three oilers in the museum鈥檚 collection include: post and chain style, twin wheel style and watermelon style.