The dogs and the sheep are crossing the wire.
It turns out that 4 wires worked, but 2 wires are not enough.
I think the problem is there is too much of a gap between the middle wire and the ground. The dogs are able to crouch and get through easily.
The solution for the dogs is to chain them to a log or an old tire. This will keep them from going to far if they try to make a break for it. The dogs need to be able to move around the land and the wire isn’t designed to contain them. They should be roaming at the edges of the property and securing it from time to time.
For the sheep? I am not sure why they are not respecting the wire. I will go back to 4 wires and then maybe experiment with 3 wires to see if they still respect it.
Down the road, I’ll need to do a better job securing the property. The dogs can leave at the back corners, so I’ll put up some pig panels to keep them from doing so. But I can’t secure my neighbor’s back 20. I’ll probably secure a pig panel to the gate to try and keep the dogs on my property. Eventually, though, when I move the animals to the back 20, the dogs will have to go with them.