Lack of vitamins and minerals will make the eggshell white and shallow.

The lack of vitamins, minerals, calcium and phosphorus in feed can make chickens lay white eggs. Vitamin D3 can regulate the metabolism of calcium and phosphorus, and its basic function is to promote the absorption of calcium and phosphorus in the intestinal tract. Vitamin C can increase the activity of thyroid, promote the metabolism of calcium and minerals, and directly or indirectly affect the quality and color of eggshell. Zinc carbonic anhydrase is needed in the process of eggshell calcification. Laying hens are zinc deficient, carbonic anhydrase activity is reduced, and high manganese also inhibits zinc absorption. Usually, each egg needs no less than 4.2 grams of calcium, and it is appropriate to add 3% to 3.5% in the diet. The peak calcium content can reach 4%.