The Potbelly Pig Promise

Dylan made a promise to his friend, Patrick. He's going to take a photograph of a real potbelly pig at his grandparent's farm. When he arrives, Dylan quickly discovers Grandpa raises everything but potbellied pigs. Later, they visit the county fair hoping to find them. Dylan sees pigs of all colors, shapes and sizes, but no potbellies. Their pens are empty.  Will Dylan ever find a real potbelly pig? And will he be able to keep his promise to Patrick?