My most successful fencing, after three years with pigs, is a wire fence with an electric fence just inside it. The fence is sheep netting with 6" square holes and the posts are made from lengths of 2"x2" from a builders supplier. I sharpened the poles and just tapped them into the ground and then stapled the wire-netting on. The electric fence is a single strand of the tape type, battery powered.
I think when the pigs see the fence and get their first shock from the electric, they accept that they can't get through. So far I've had no escapes and the whole lot can be taken down or moved quite easily. I take away the battery for charging every few days and they don't know it's off. Instead of a gate I have a stairs on each side, made with six 9" blocks (3,2,1 on each side). Braces and a belt, I suppose.