CRISPR has you covered:
"scientists warn that they may be a distraction from more serious research" - understandable, they're really cute - I'd be distracted, too.
I mean this, as friends that do this: Have a pig for around 9 months to a year (they do grow fast, I understand most pork sold is from 3-9 month old pigs) living and kicking around on the farm. Well fed, well raised. And appreciate the meat, and not as a commodity.
One of my neighbors bought one, I saw her out walking with it and asked her what she was going to do with it when it was 200 lbs. She didn't believe it would get that big, but it did. I never did find out what happened to it.
Given the popularity it seems there would be a "market" for a small breed of pig. But if small ponies is any example it would not be a good deal for the animal.
SO I can't help but wonder, why can't we breed real Teacup Pigs? We can breed real Teacup dogs, tiny cats, hell we can even breed tame foxes and even Miniature cattle[1]
If there really is such a big market, any many pig owners love their pets, why doesn't someone actually selectively breed for tiny adults?
1. I'm not sure we've tried. Maybe it's possible, but we've never tried.
2. If we have tried, and it hasn't worked, it's possible there's not enough genetic diversity in pigs. Dogs have an enormous amount of genetic diversity, which is part of why we've been able to get breeds that look like entirely different species. There are many breeds of cats, but I haven't seen any that are as radically different as, say, a chihuahua and a mastiff. We bred tame foxes, but they weren't radically different from wild foxes. (The different physical traits, I think, were their ears were floppy, and some retained juvenile markings into adulthood - similar to dogs.)
Considering you can't buy dog meat at the grocery store, there are certainly exceptions carved out for "livestock" animals versus pets. As far as I can tell, those exemptions are by species and not by "purpose."
Googling a bit, I found California Penal Code 597.3, which contains one example of specific exemption in a live-animal retail scenario. "Provide that no animal will be dismembered, flayed, cut open, or have its skin, scales, feathers, or shell removed while the animal
is still alive." In a subsection, any poultry species is specifically exempted.
I am not a lawyer and I am having trouble focusing between legalese and descriptions of cruel acts, so I am going to stop hunting for examples.
http://www.nature.com/news/gene-edited-micropigs-to-be-sold-...