Signs of a Vitamin A deficiency may not show in an adult bird for several months, depending on the amount stored in the liver. Day old chicks may show signs after seven days, but if adequate reserves of Vitamin A are passed down from the breeder hen, this period may extend to several weeks.
- emaciation, weakness, ruffled feathers
- drop in egg production and hatchability
- increased embryonic mortality in incubated eggs
- watery eyes
In chicks
- growth retardation
- loss of appetite
- drowsiness, weakness, incoordination
- ruffled feathers
Required for the normal absorption and metabolism of calcium and phosphorus.
- loss of egg production
- poor shell quality -even if calcium and phosphorous is available
- osteoporosis
In chicks
- Retarded growth and severe leg weakness
- soft and pliable beaks and claws
- difficulty in walking
- rickets
In chicks
- cerebral softening (encephalomalacia, or crazy chick disease)
- weakening and wasting of the muscles (muscular dystrophy).
- tremors
- oozing of fluid from cells and tissues.
In chicks
- Impairment of blood clotting
- subcutaneous and internal hemorrhages
In chicks and growers
- reduced weight gain and feed intake
- poor feathering
A deficiency can only occur is there is a deficiency of tryptophan
- general weakness
- loss of appetite
- diarrhea
- reduced egg production
In chicks
- bowing of the legs
- dermatitis on head and feet
- enlargement of the ankle joint (tibiotarsal)
- black tongue in 2 week old chicks
- retarded growth
- reduced egg production
- reduced hatchability
In chicks
- brittle feathers
- reduced growth and feed intake
- dermatitis affecting the corners of the beak, underneath the beak, and the feet
- poultry are more susceptible than other farm animals
- poor feathering
- slow growth
- anaemic looking white and waxy comb
- dermatitis of the feet and skin around the eyes (similar to pantothenic acid)
- perosis (retarded growth and deformation of leg bones)
-
- loss of egg production
- loss of fertility
- reduced apetite
In chicks
- retarded growth
- anaemia
- dermatitis
- nervous movements of the legs
- lethargy and head tremors
- neuromuscular disorders
- star gazing, and weakness
- convulsions
- anorexia
- polyneuritis (inflammation of the nerves)