MICRONA™ Poultry Grit is derived from calcium carbonate. As a grit source, it is superior to oyster shell – shell is not hard enough to do the digesting task grit will. Most laying poultry will benefit from MICRONA being offered free choice. Because of it’s pH adjusting qualities, MICRONA will also keep coops and runs hygienic and clean. Just sprinkle a handful per square foot, then spread your bedding material.