I sell my pups to a pet shop. The lady who owns the store used to breed and show guinea pigs. She buys guinea pigs from me, and also gets some, though not many, unwanted pigs. She will refuse to sell a pig to anyone who she feels wouldn't give the pig proper care, attention, and a good home, and has before. The store will take back any pigs sold there for any reason, but due to screening potential pig owners, few are ever brought back.
Owners can call with questions, and many also buy supplies at the store.
To my knowledge there are NO pig shelters in the state of Kentucky. In my area, with one exception, there are no shelters that will even take guinea pigs. They sell guinea pigs for the same purpose. Of course they don't ask questions to see if the purchaser will be a good home. It leaves no place whatsoever for the caring, responsible breeders and pet stores, or the places that are not overflowing with pigs.