Teacup pigs is a misleading name sometimes given to baby potbelly pigs by sellers. According to Modern Farmer, unscrupulous breeders give the name to very young pigs, along with a promise that the pigs remain very small when full grown. In reality, full-grown pigs usually weigh more than 100 pounds.
Some breeders instruct new teacup pig owners to deliberately underfeed their new pigs in order to keep their sizes down. By ensuring that the pig does not get the nutrition it needs to grow, its size may be somewhat stunted in adulthood. However, feeding pigs according to these instructions results in malnutrition and associated health problems.