Not knowing who owned them, I called the police. My top concern was that they would wander onto the main highway and cause an accident. They were about a half mile from the highway and were heading that direction. Failing to be able to get around them and thus drive them back up the mountain and into some neighbor's pasture for safety, I helplessly stood guard to prevent a vehicle from coming down the mountain, thus hitting or spooking them further down to road. They continued to head for the highway and I can only hope that the police arrived in time to block the end of the road. Guess I'll hear the neighborhood gossip tomorrow as to what finally happened.
Keeping livestock adequately confined can be difficult, but it's the responsibility of every livestock owner. And it's always a nightmare when they break out. On my own farm I check the condition of my fences daily, looking for weak or damaged spots. Even so, I've had livestock escape, usually because a fence section was brought down by a fallen tree or weakened due to acid rain. Most of my stock is behind double fencing, which helps a lot to keep them in my own property. So if I notice that the pigs have escaped, they are still behind the second fence that completely surrounds the farm perimeter.