Vitamin D Deficiency Overview
Vitamin D3 is an important nutrient for chickens, especially for growing chicks and laying hens. In young chicks, a vitamin D deficiency can cause rickets, resulting in leg and beak deformities. In hens, a vitamin D deficiency adversely affects egg production and can cause calcium deficiency.
In order for absorption of calcium (Ca) and phosphorus (P), adequate levels of vitamin D3 must be present. Chickens can get vitamin D3 in their bodies through two different routes---by ingestion of it in feed or by exposure to sunlight.
Make sure not to go overboard with the Vitamin D3
When chickens receive too much vitamin D3 it can result in excess calcium in the blood which is referred to medically as hypercalcemia. This is a serious condition which can lead to gout, heart problems, and liver damage. A clinical sign of too much vitamin D3 in the diet of laying hens is the production of eggs with calcium pimples on the eggshells. When the pimples are scraped off they will leave tiny holes in the shell.