Occurrence: Worldwide. Species affected: All. Age affected: All.

Causes: Deficiency of vitamin B2 (riboflavin) in the diet. Most grains are deficient in vitamin B2, therefore it must be included in the premix.

Effects: Curled toes, poor growth, weakness and emaciation are seen in young birds. Leg muscles are atrophied and flabby. The skin is dry and harsh. In adults, poor hatchability and egg production can occur. Dead embryos have "clubbed" down...