Toby has cracks, etc. I started him on SmartPak SmartHoof
SmartHoof - Hoof Supplements from SmartPak Equine soon after I got him 7 months ago. The last farrier that came out remarked without prompting that he could see the horse's nutrition had changed for the better about 6 months ago. I hadn't told him when I had gotten the horse.
Half of his hooves are still in rotten shape, but the new growth is so much better, we just have to get him to the new stuff.