Calcium Carbonate vs Oyster Shell | BackYard Chickens
Sep 11, 2017· I''m debating whether I should get 50lbs. of Calcium Carbonate Grit made by MICRONA. Here is the product description: "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.