Chickens need a high level of calcium in their diets, without a sufficient level of calcium egg shells would be thin and brittle. Jondo mixed poultry grit has two types of grit mixed in suitable proportions for your birds. 1. Insoluble hard grit which has grinding action in the gizzard enabling the bird to digest food properly. 2. Soluble soft Calcium Grit, which dissolves into the birds system and ensuring your hens health and egg quality Grit is best fed on the ground or from a poultry grit feeder. You will be able to tell if your chickens require extra calcium in their diet as the eggs they lay will have poor quality shells. Even if the shells are healthy, extra grit in the diet will not harm the birds. The grit is very easy to store and should be kept dry if possible.