Spaying or Neutering Your New Pet Pig
A good rule of thumb with any household pet is that spaying & neutering makes for a better companion. Unless you are purchasing a mini pig with breeding in mind (and have the outdoor facilities at your home to accommodate the effort) you'll want to spay your pet as soon as possible.
Unfixed males (boars) will eventually reach sexual maturity. Two concerns come immediately to mind. The first is that boars produce an odor through the glands that is utterly repulsive to anything but a lady pig! The smell is on their breath & body and will eventually be on everything you own including furniture & clothing. If you plan to breed, you will want him to be an out-of-house pet. Trust me. The other concern with unfixed males is that they will rub against & mark & become amorous with animate objects (you, your kid, your dog, your cat) and inanimate objects (shoes, pillows, furniture, the kitchen sink!) with insane frequency.
If choosing a female, the same rule applies. You'll want to get the little lady spayed because females come with their own set of undesirable habits. Female mini pigs, despite recognizing there are no boars around, will begin to mark everything they can find in effort to lure a willing fellah into their midst. This isn't something you want done to your furniture or favorite shoes.