"A litter box?" you ask, "For a pig?"  Definitely.  We use the huge black plastic wash tubs available in most hardware stores and cut one side so our potbellied pigs can go in and do their business.  We use wood shavings and "oderase" from PA Heartland to cut down on any smells.

Here's what the experts have to say about litter boxes:

• In her book, Pat Storer writes: "Wood shavings make ideal litter for the box. Avoid cat litter, which the pig will most likely taste and sometimes eat."1
• In their book, Kayla Mull and Lorrie Blackburn write: "Choose a box that is not too tall, but easy to get into. Fill it half full with nontoxic white pine wood shavings. Use shavings instead of kitty litter because shavings do not cause problems if the piglet eats them."2
• In her book, Jackie Beshur writes: "Have you discarded clay based cat litters which hurt pig lungs? Have you discarded cedar shavings which are believed to be toxic?"3

Notes:

1. Page 19, Pot Bellies and other Miniature Pigs: A Complete Owner's Manual, by Pat Storer. NY: Barron’s, 1992.
2. Page 127, Pot-bellied Pigs: Mini-pig Care and Training, by Kayla Mull and Lorrie Blackburn. Orange, CA: All Publishing, 1990.
3. Page 37, Good Intentions are not Enough: Pot-bellied Pig Care and Training by Jaki. Beshur. 1993.

Tip:  Is your pig urinating where s/he shouldn't?  After cleaning the area thoroughly, feed them there for a week or two.  Pigs are incredibly clean and will not use their dining area for a bathroom!  Then, feed them where you normally would -- but place some food -- a few pellets -- every so often -- where you potbellied pig urinated as a reminder that they might get fed there!