We use white rope electric fencing for our little flock, the theory was that it's more of a visual barrier than wire. We're newbies to sheep keeping and originally had problems with one ram lamb escaping (and nibbling at my cider apple trees, the little beggar). My (very clever and patient) wife watched and found that he was pushing under the bottom rope. Of course, muggins here had left the power off on the very low bottom wire to stop it grounding. Anyway, I now strim the length of the fence when I move them and keep the bottom rope live as well. That's worked without any dramas so far. We do use a 4 reel system for the sheep, but maybe 2 would be enough if there are no lambs.