Want your chickens to have a ton of calcium AND get the benefits of herbs? Our Herbal Oyster Shells are a fun combination of: Oyster shells, Basil, Rose, and Oregano that your chickens are sure to love! Calcium is necessary in your flock's diet for: Strong egg shells, Consistent laying, Reduce calcium loss in bones. Directions: Mix Herbal Oyster Shells with your flock's daily feed or offer separately. Provide fresh water at all times.