Sounds like you didn't pick your neighbors very well
But seriously, I don't think it will stop unless you make it impossible for the two Casanovas to touch each other, even only nose on nose.
And even then they might be still running the fence constantly.
I used to have a barn at a big Standie breeder who had long narrow paddocks with 12' distance and high electric fencing and he still had problems having two stallions next to each other. They did their own training in there, even without mares anywhere near.
It would help if your neighbor would put up some extra fence on his side, too. Any chance of that? Posted via Mobile Device