Pigs have disappeared

Doug went up to feed then this morning and they were not in their enclosure. He found that some poles near the top of the fence were down.
We have spent much of the day searching for them and visiting the 3 nearest neighbours so that they can be on the lookout.
We find it suprising they have so thoroughly disappeared as the couple of times they have got out before they just snuffle off to the nearest bit of food. In this case with chestnuts everywhere that is not far at all. We probably covered a radius of more than a kilometer searching for them and they can hear us from a distance so we would expect them to come back to get their breakfast when they heard us.
We have heard stories of wild boar mating with domestic pigs and we wondered if the wild boar in fact knocked the fence down as it had fallen inwards.
Now all we can think of to do is spread some trails with their food to attract them home and wait to see if they turn up.
We are obviously quite upset as we have put a lot of work in to them and they are just about ready - perhaps they heard our plans for their future and have done a runner...