The uncoordinated absorption of calcium and phosphorus will make the egg shell white and lighter.

In the body, the absorption of calcium and phosphorus has a synergistic effect, and an appropriate amount of phosphorus can promote the absorption of calcium. During the peak laying period, the ratio of calcium to phosphorus was 5 to 6: 1. It is reported that low phosphorus can increase the thickness of eggshell and improve the quality of eggs. Nutritious white-shell eggs are most common at the beginning of laying hens, there will be a large number of white-shell eggs and soft-preserved eggs, which generally decrease with the increase of age and the supplement of vitamins, minerals, calcium and phosphorus.