Digby was the size of a kitten at six weeks old
A woman from Telford who paid £700 for a micro pig says she is concerned that other pigs like hers will be abandoned.
Lisa Turk from St Georges said the pig she bought in November 2009 was described as a micro pig but it now weighs seven stone (44.5kg).
The 37 year-old said she heard the pigs could be kept indoors but her pet called Digby has outgrown the house.
Miss Turk said she was worried other people may buy pigs and then abandon them when they get too big.
Digby is a cross between a Kune Kune, a Gloucester Old Spot and a Tamworth pig and at six weeks old he was the size of a kitten.
Miss Turk, a business development executive, said she was "disappointed" he had grown so much, but added that Digby was a much loved pet and they were now looking to rent some land and buy another pig to keep Digby company.
However, Miss Turk was keen to raise awareness about the level of care needed by pigs: "They're farmyard animals, there's no way they should be kept in the house - it's not fair for the pigs - their natural behaviour is to be outside rooting... at the end of the day they're hard work."
Rob Rose from
Valley of the Pigs
, founder breeders of British micro pigs, said everyone who sells micro pigs have a duty to give people the right advice.
He added that anyone interested in having a micro pig should think carefully about the environment where the pig will live and conduct thorough research.
Gwen Howell, a
rare breed pig farmer
from Cardeston in Shropshire, said taking on a livestock animal is a serious consideration, there's a lot of paper work involved and regulations regarding animal movement apply to pet pigs.
Ms Howell said: "You can't take a pet pig for a walk, as you would a dog, and regulations also apply to what pigs can be fed which totally excludes kitchen waste... so you can't even feed them potato peelings or apple cores."
The Royal Society for the Protection of Animals (
) has also expressed concern about the suitability of micro pigs as pets.
The charity said owners must ensure they have the time, finances and facilities required as well as access to specialist veterinary care and the ability to comply with the many laws surrounding pig keeping.
The RSPCA added that without such considerations it was worried about the fate of micro and mini pigs once the novelty of owning them had worn off.