An adult laying hen (over the age of 18 weeks) needs between 4-5g of calcium per day which is often not found in their regular diet. This increases eggshell integrity, helps control muscle spasms, especially those used while laying an egg, ensures proper bone growth and development and is needed for the absorption and utilization of phosphorus. Why Oolitic Aragonite is superior to other forms of calcium supplements? Oolitic Aragonite is the world's purest form of the Ocean's naturally precipitated calcium carbonate. It has a crystalline morphology of orthorhombic, bipyramid crystals with an extremely high surface area and aspect ratio giving aragonite bioavailability (calcium uptake) superior to any other calcium form.