Thanks to all who responded with suggestions to help my mares legs (Truman, Karen, Bonnie, Lynn and Peggy.)  I wish I had asked sooner!  It was often suggested that my mare might have a fly bite allergy and sun sensitivity, which could also leave her skin damaged and open to fungal infection.  So first I'm going to try using Desitin (since I have it on hand) to control the flies, sun, and soothe her skin.  After a week I'll see if there's improvement, and if needed I'll start with some of the other suggestions which were interesting, but I'll have to locate the items.  I hope there is no fungus involved.  Thank you all so much for the support!!!
 
Linda