I must say this question bothered me. Pigs are actually some of the cleanest animals, but due to the disablitity they have, not being able to sweat, they must roll in mud to keep cool. Pigs will actually try very hard to keep clean, however they often end up rolling in the mud so they do not die of over heating
Pigs are omnivores that live off of a wide range of food similar to humans. In the wild, pigs are foragers, mostly eating leaves, roots, fruits, flowers, and grasses. When being raised or farmed by humans, pigs are commonly fed corn and soybean meal with added mixes of minerals and vitamins to help the pig maintain a healthy weight or to gain weight.
There are many similarities between pigs and humans, making the perfect subject for human medical research. Pigs also carry many of the same parasites and diseases as humans and can also transmit those diseases to humans they come in contact with.