Welcome to the world of sheep! If you look at any field of them you will invariably see at least one limping. However, a simple way to cut down on limpers is to have a heap of lime somewhere where they will walk through it - like in a gateway or near a water trough. The lime seems to dry up any simple problems like scald. Just any ordinary lime will do - like a bag from the garden centre or builders merchant if you just have a few sheep. If you have a lot, then some left over from liming your fields. It doesn't work immediately - may take a few days, but you suddenly notice that everyone's walking ok again.