The fence would also keep out next-door's tup if he was a bit quicker than you at sensing that Tonight's The Night. It would keep the ewes from sneaking over to join him too. They have their own ideas about suitable genetic partners and the timing of their pregnancies.
We used to keep two Jacob ewes on half-an-acre of fairly tatty rough grass, We got two fleeces a year, and in Novenber they went for a nice holiday with a flock of aristocratic Jacobs at a castle a few miles away, producing cute black-an-white Jacob lambs in due course. I am sure they looked forward to their hols, they never objected to being rounded up and transported off.
Next door to us they had sometimes kept sheep (ordinary white type) and they still had an nice old tup with arthritis, kept on as a pet. He could hardly get up if he lay down, and they kept saying they would have to get rid of him soon, he was so old and doddery.
In mid-October one year, one of our Jacob ewes was discovered to have somehow got through the wire, and was peacefully grazing beside the old boy. "No harm done", we all said, "He is too old and too decrepit for any shenanigans."
Come March the evidence appeared - two lovely pitch-black lambs. To old my eye!