It’s probably not possible.
But here’s what we’ve learned so far.
1) Pigs’ noses are tools comparable to pry-bars connected to jackhammers. They dig with them, and destroy things with them, and rip things up with them, and pry things away with them. This includes fencing.
2) Pigs delight in escaping from fenced areas. They like to forage – it’s what they’re built for!
3) A woven-wire fence is good – unless they’re piglets, in which case they squeeze right through the squares. Farm stores sell pig panels – panels of woven-wire fencing that have small squares down low, and larger ones up high.
4) Even if your fence is touching the ground, they’ll get under it. Noses = pry-bars. So, burying it several inches below the ground level is the best idea.
5) Pigs squeeze between things.
6) If they do get out, they know where home is, so they won’t run far, if you catch them soon. And if you bring a bucket of grain – they’ll come running!
7) When they do escape, your frustration causes you to think of how tasty that bacon will soon be…
8 ) Electric fencing, low to the ground (low enough so they can’t slide under it without touching it, and high enough so they can’t step over it without touching it), is probably the way to go. However, once you train a pig to respect the electric fence, they’ll never cross that line again – even if you take the electric fence down, they still won’t walk over the path where it used to be! We haven’t used our electric fence yet, but we may soon…
9) A small, sturdy, portable pen is ideal. This means either electric fencing or movable panels. Pigs destroy an area of turf quickly – but this can be turned into a boon. Farmers such as Joel Salatin use pigs to turn over and fertilize land – pigs rooting instinct is a natural way of aerating the soil, composting organic matter, and fertilizing it with manure. They simply must not be allowed to stay in one place for a long time: after one patch of land has been “worked,” they must be removed from it and taken to another. The freshly-turned-over patch should then be allowed to regrow for about a year.
We used electric fencing and it works like a charm! See this post for more details…