I just got my Clydesdale last week so am very new to draft breeds. I was washing his legs trying to get all of the mud out of his feathers and I felt some strange almost hook-like projections at the back of each leg (around the fetlock area). They are on all 4 legs and upon further investigation appear to be black. Are these normal? If not, any idea what it could be? I tried googling but wasn't really sure what to look up.