My mare has recently been short striding on her right hind but only at a walk and only when being ridden. She is showing no signs of heat or swelling, no previous injuries, no ill fitting equipment, no sore back and still loves to work. She has no problem doing whatever I ask under saddle and plays and walks like normal in the field so I'm out of ideas. My farrier did say she has low heels in the back end but I'm trying to stay away from shoes. Help?