As long as the pig can't run off into a street, or somewhere else that is dangerous , is is okay for them to run around your property, just stay with them. Pigs can run fast, but usually in short bursts. If you can, I would suggest setting up a large fenced in "show ring" to practice in, until you trust your pig. You can use fencing panels, chicken wire with some poles, just something to deter them from running off.