Our horse manure is the best there is for mushroom cultivation. All of our manure originates from purebred horses that are fed Grade-A, non-GMO diets. This manure is antibiotic-free. We only use manure that has been naturally leached by the rain and uniformly dehydrated by the sun. All of our equine manure is shredded for your convenience and to assure that you receive a greater volume of manure than you would from other online vendors.