Calcium is an essential nutrient for chickens as it has vital role in egg production, controls heart rate and blood clotting, promotes a healthy nervous system, supports growth and development and boosts bone strength. Not only does chickens need to build and support healthy bones, but they also need enough free calcium in their diet to produce a hard eggshell. Calcium affects hormone production, reproduction and controls muscle spasms that helps in the egg-laying process, which is essential for the formation of eggshells. Calcium utilization depends on vitamin D and phosphorus. Vitamin D is a fat-soluble vitamin that affects calcium and phosphorus metabolism and regulates the amount of calcium to be released from the bones into the bloodstream.