Rupert & Tia
Mama Doe
The idea of the electric fence is that foxes prowl around an area sniffing at the ground and looking for a way to tunnel under something to get t. The fence gives them a jolt when their nose touches it and they are warned off. It is not 100% and tou have to watch for highpoints nearby (sheds etc) they could jump straight off of. However a fox that will plan to leap clear over an electric fence without exploring it and getting zapped first is a very very unusual one. Free range hen keepers use these fences to keep entire flocks safe.
I'm well aware of how an electric fence works, as I used to work in a country store, selling them, and we had to do training on them, and foxes can get round them (as several of the farmers found out and lost animals because it was the only pretection they used). One or two buzzes from the fence and they run off.... but they learn not to do it again.