Roup, Hypovitaminosis A, Follicular Hypeerkeratosis, Phrynoderma, Squamous Cell Hyperplasia
Vitamin A is a generic term that encompasses a number of related compounds that are essential fat-soluble molecules predominantly stored in the liver. Vitamin A comes from two sources. One group, called retinoids, comes from animal sources and includes retinol. The other group, called carotenoids, comes from plants and includes beta-carotene. Vitamin A is necessary for vision, growth and tissue differentiation. It is important for keeping the eyes, skin and inner linings of the bird's body healthy and resistant to infection. Vitamin A is also needed for the maintenance and growth of beaks, nails, feathers, bones, and glands.
Vitamin A Deficiency in Chickens
Vitamin A deficiency occurs in malnourished and chronically sick chickens that are not provided any access to fresh green forage or other foods containing high levels of vitamin A. It causes abnormal vision adaptation to darkness, dry skin, increased nail breakage, and decreased resistance to infections. This is because a diet deficient in vitamin A causes disturbances to the protective mucus lining surrounding the outer layers of the chicken's esophagus (throat), oropharynx (oral cavity), paraocular glands (involving the eyes), sinuses (nasal cavity), proventriculus (stomach), and bursa of Fabricius. Research conducted by the Department of Animal Science at Shandong Agricultural University in Shandong, China that was published in 2015 showed that vitamin A deficiency suppressed the immunity of the airway in young chicks, leaving them more susceptible to infections involving the respiratory tract.
Risk Factors for Vitamin A Deficiency
- Malnourished or starved chickens.
- Feeding chickens feed which has been stored for longer than 60 days.
- Lack of access to fresh forage.
- The chicken has an underlying condition that is causing an impairment in vitamin A absorption or storage.
- Vitamin imbalances
Vitamin A Recommendations for Chickens
|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|