I know somebody who bought 2 pommeranians, yes i know they're not pigs but please bear with me. The puppy was teeny tiny and very much the runt of the litter. Once they were home and settled in the 2 pups would do what puppies do and run around and play and scrap. When they took them to the vets for vaccs the vet commented on how small she was and that he was concerned about her

she went home and carried on doing what she was doing then one day she keeled over and died

turned out that her body WAS to small for her insides and she had a heart attack. Not sure why she was so small wether it was simply a genetic fault (same as so called micros) or if she didn't get what she needed from mum when she was born.
My point is if there are defects in anyway surely it is not a good thing to promote these? For the vanity of humans these poor animals suffer. As i said in another post, these poor creatures are being exploited as the newest and most fashionable pets.
Sry another 2p worth
(yes i know i am by far a pig expert but i know when animals suffer)