"Chestnuts" are irregular shaped dark areas of hard skin located on the inside of your horse's legs. Current theory of the genesis of chestnuts is that they were vestiges of footpads from thousands of years ago. Because the chestnut is living tissue, it will continue to grow. Consequently, the chestnuts on a horse can be sensitive and can cause discomfort if attempted to remove, peel-off or rasp them flat with the skin. A better method to groom the chestnut is to apply petroleum jelly to the chestnut and allow it to soften. Often, the protruding portion of the chestnut will gently fall off after a day or so. This technique for softening the chestnut can be repeated as needed. If the chestnut does not appear to be causing any problems to the horse or if it is not unsightly in the show arena; leave them alone. They will fall off in their own time....