Recommended for Stage Three laying poultry and waterfowl, the calcium found in Cluckin' Good Oyster Shell is absorbed by laying hens to build strong eggshells. Feeding your layers Cluckin' Good Poulty Grit helps to digest feed for all stages of life and contributes to the digesting of whole grains and oyster shell. Oyster shell is not a substitute for grit. | Scratch and Peck Feeds Cluckin Oyster Shell Chicken Supplement | Size 4 lbs