Pigs are actually among the cleanest animals. In fact, MSNBC writes, "They are perhaps the smartest, cleanest domestic animals known - more so than cats and dogs, according to some experts. But pigs don't have sweat glands, so they roll around in the mud to stay cool."
And they're intelligent, too. In fact, while chimpanzees are known for their smarts, pigs might be just as intelligent. Pigs are able to solve problems that require they understand relationships and rules. For example, researchers trained them to move a cursor with their snouts. Then they were tasked with using the cursor to differentiate scribbles they were familiar with from others they were just seeing for the first time. Pigs learned how to make the distinction just as quickly as chimpanzees, our closest living relatives.
Pigs also have distinct preferences. As Shapiro found out on her regular visits, Jason is a very discerning pig. Recognizing his loyal visitor (and bearer of food) when he sees Shapiro coming to his enclosure, he gets as excited as one would expect a dog to be when his person comes home, running back and forth alongside the fence and greeting her with enthusiastic grunts.