I've never noticed this before and wondered what may be causing it. My two teenage geldings have a noticeable red tint to them. One is sorrel, one is black. I'm racking my brain trying to figure this out. The only thing I've changed is that I started offering loose minerals a week ago, with little interest to them. I also started giving the black one a pound of hay stretcher pellets with his feed because I noticed him triple chewing his hay. The sorrel guy gets a couple of handfuls with his, just because. I did deworm them a week ago, with zimectrin gold, but I've done that before and never noticed a change. Could they be lacking something in their diet? My vet is scheduled in 3 weeks. Should I be concerned?