When teaching a pig to go to the bathroom, you must provide regular breaks. Start when the pig first wakes up, as well as after each meal. You should also take it every hour or so between those times and right before bed.  You can either take the pig to the box or to the same place in the yard. You can also teach a combination of the two, taking the pig to the box at certain times and outside at others. Just like a dog, a pig can be trained to learn certain commands. If you use the same phrase for going to the bathroom, your pig will come to associate the activity with the phrase. For instance, you could try "Go potty," "Bathroom time," or "Outside potty." Say it each time you take your pig to the bathroom, particularly when the pig starts actually going. Once the pig has gone to the bathroom, immediately offer it praise. Say "Good piggy," or "Good pig!" Use a bright, happy tone so that the pig gets the idea it's done a good job. Your pig is going to have accidents in the house. However, punishing when you find the accident isn't going to do any good. It won't connect the punishment with the action of going to the bathroom. If you catch your pig using the bathroom, then you can say "No!" firmly. Take them to where they should use the bathroom. Food rewards aren't needed and may even be detrimental. Pigs like learning habits, and adding food may confuse them. Plus, they're smart enough to game the system, tricking you to take them to the bathroom when they want a treat.

Summary:
Take the pig to the bathroom regularly. Have a bathroom phrase. Use praise as a reward. Skip punishing mistakes. Avoid treat rewards.