A Complete Oystershell Grit from Extra Select
Oyster shell grit is used to provide poultry with enough calcium to produce strong bones and good egg shells. Modern poultry laying feeds usually contain sufficient calcium but there is no harm in providing some additional calcium in this way, particularly if poultry are being fed on household food or straight cereals
Chicken need a high level of calcium in their diets to produce eggs, and without a sufficient level the eggs shells would be thin and brittle. A good quality grit is the best way to introduce calcium to a chicken's diet.