Quite a coincidence that the burial of stones in the thirteenth century coincided with the monks clearing land to accommodate huge numbers of sheep. The sheep snapped by Moss have been treated yet still habitually as you point out rub up against the stones, and of course undermine the areas around the stones by congregating and sheltering, so might topple if they weren't stuck in concrete. Shepherds back then had to treat and replace sheep at their own expense, they carried tools to snip wool from the rear end to discourage fly strike and to deal with bloat, and had lamb warming pockets just like the modern Barbour. I bet you would still be able to make it serviceable had it say been buried beneath a stone for 700 years :)