Bill B.'s Cornerstone system composts the manure from 15 horses. Initially, Bill composted the wet spot bedding with the manure but, after a few months, he found that he gets a much better compost product when most of the bedding and hay are kept out of the aeration bins. The "leftovers" are hauled to a site that the county uses to create mulch for public sale. His finished compost is used as a fertilizer on the pastures.