We always had our feeder pigs on pasture when I was young. Started with woven wire on the bottom... but they eventually had that ruined... After that, we always kept them on the pasture with a single hotwire placed about 8 - 12" above the ground. If they were able to root enough to bury it they'd cross it, but for the most part, it was effective. Our sows were always kept on pasture except when pigging. The little pigs would go out under the wire, until they got big enough that they couldn't squirt through underneath anymore.
Point is, they DID respect that wire. Ya'll tried this already though I suspect?
I don't use hot wire any where any more. It's too maintenance intensive.
Years back I planted an oats patch for several years and used those white stakes between t posts. I had two hot wire spaced evenly down low. One maybe 6" up and another maybe a foot higher, then one up around waist high for cows. It did keep the pigs out. It was just an constant deal to fix posts and stuff because of all the deer.
Interesting story on pigs and hot wire. Most of the farmers I use to hunt for would hotwire their grain fields off. They smoked their turn tows with round up any way so maintenance was not as bad. It worked good during planting time but once hit roasting ears or the milo headed out it didn't stop much.
I was on a big ranch one evening. We pulled in to hunt about 10K acres of corn. The dogs were going crazy winding hogs from the brush. We were unloading buggies and getting set up when we say some hogs come up to the hot wire. We kept watching and more and more hogs started piling up on the brush side. It was pretty odd begavior so we were all watching and even crawled up on trucks to see. We though dogs or coyotes or some thing were after them. They looked like hogs that were based up in a group.
All the sudden they all started squeeling and raising hell. They all charged that hot wire at the same time. They started squealing about 20-30yds before and they squealed about 20-30yds after.
That's pretty dang smart.
Another time when o was a teenager a farmer put some short tposts in right next to the corn with hot wire. We actually had to drive on the outside of it to hunt thw field. We expressed our dissatisfaction with it but in true farmer fashion he wanted to do the easiest thing for him.
We had been hunting for several hours that night. We had a bay and I went to jump down off a high seat on the back of a gator. When I did I came down on one of the posts. It caught me just above my left knee and cut up the inside of my thigh for about 6". Luckily I hang to the right. My career was almost ended early.
...
When we went back 2 days later and the whole fence was moved to the outside, well away from the road. It scared that farmer pretty good.
