A pig farm enclosure is a structure built to contain pigs, usually for the purpose of raising them for food. The most common type of enclosure is known as a STY, which is a three-letter word that is one of the solutions to this crossword puzzle. A STY is typically an open-air pen with a roof and walls made of wood, metal, or other materials. It is designed to provide shelter and protection for the pigs while allowing them to roam freely.