Layers mash should contain a high percentage of calcium. This is because calcium is a vital mineral that is essential for eggshell formation in poultry. Laying hens require a sufficient amount of calcium in their diet to lay eggs with strong, hard shells. Calcium deficiency in hens can lead to soft-shelled or shell-less eggs, which are prone to breakage and can cause health problems for the birds. Therefore, it is important to provide layers with a diet that is rich in calcium, typically provided in the form of calcium carbonate.