Vitamin A Deficiency

Vitamin A deficiency is most likely to occur in chickens receiving an improper diet, heavily parasitized, or who are suffering from conditions that interfere with normal digestion. Also, vitamin A requirements are higher for chickens under stressful conditions such as abnormal temperatures or exposure to disease conditions.

Chickens with vitamin A deficiency have an increased risk of getting sick. The two main mechanisms involved in the prevention of disease are the effect of vitamin A on the immune system and on epithelial integrity. Vitamin A deficiency also impairs regeneration of normal mucosal epithelium damaged by infection or inflammation and thus can increase the severity of an infectious episode and/or prolong recovery from that episode.

Vitamin A deficiency presents as a number of different clinical manifestations, ranging from xerophthalmia (dry eye), uropygial gland infection, impaired growth, and increased susceptibility to severe infection. It affects ocular tissue in two ways: by slowing the regeneration of the visual pigments following exposure to bright light and by disrupting epithelial integrity.

Nutrition Requirements

Vitamin A Recommendations for Chickens

Age/Life Stage	IU/kg
Newly Hatched Chicks (0 - 10 wks)	12,000-13,000
Young & Growing (10 - 20 wks)	10,000-12,000
Laying hens (Actively laying eggs)	8,000-12,000
Breeders (20 wks & older)*	10,000-15,000
Broiler/'Meat' Breed Chicks (0-18 wks)	10,000-12,000
Broiler/'Meat' Breeds* (19 wks & older)	12,000-15,000
*Includes roosters