As Homestead Hacks mentioned, pigs can be potty trained, and you can even train them to use a litter box. They're also hypoallergenic, so if your family has allergies, it's a safe pet to have around.

Pigs like to root, and unless you want them rooting in your carpet, they'll need somewhere to do it. They can also be noisy and will eat anything and everything that they can.