I would never put any clothing on piggies, be it furry or skinny.
just think what could happen! they can get stuck on hayracks, sharp corners of houses, they cant scratch and clean themselves properly, and might actually get their claws get stuck on the fabric of the coat! also i imagine they would get soiled easily and then the piggy couldnt even get rid of the dirt..
no, def. a big NO from me. poor things.