Having a sound perimeter fence is important to avoid liability problems with hogs damaging neighboring properties or being on public roads. High tensile fence, woven wire, and hog wire can all be used for perimeter fencing of hogs. Fence height should be at least 40 inches. Bottom wires should be close enough together (1.5-2 inches) to prevent baby pigs from getting their heads between wires. Having an electrified wire near the bottom of the fence helps prevent hogs from digging under the perimeter fence. If using high tensile fence, 8-10 strands with the second and fourth wires electrified should be sufficient.
Interior fencing can be simpler and much less expensive to construct than perimeter fence. Electric fencing works well for divider fence. Hogs can easily be trained to electric fence. A two strand electric fence is sufficient to keep hogs in a desired area. For sows and growing-finishing hogs, wires at 10 and 18 inches above the ground will work well. If you are concerned about containing nursing pigs as well, then the bottom wire should be about 6 inches off the ground.