Organic Chicken Supplement Kit (Diatomaceous Earth, Oyster Shells & Layer Grit) Diatomaceous Earth w/ Calcium (5 lbs.), Oyster Shells (5 lbs.), & Grit (5 lbs.) Complete Chicken Supplement Package Diatomaceous Earth w/ Calcium (Organic): Pest protection both inside and out. Oyster Shells: Natural calcium source for laying hens. Grit: Supplement to help chickens properly digest feed.