Hardly ever / never seen in Canaries if you feed them properly
Lack of dark green leafy plants in the diet.
The respiratory system is the most commonly affected, however other organs can be diseased brought about by the lack of [A]. Look inside the bird's mouth to see the early signs of this deficiency. Initially, you see small white spots on the roof of the mouth and/or at the base of the tongue. The spots become infected forming larger abscesses. Depending on how bad these lesions become, the bird could starve to death.
To ensure your bird against a vitamin A deficiency, provide foods with deep green leaves such as, broccoli leaves and flowers, endive, dandelion leaves, spinach, carrots, turnip leaves, egg yolks, OR the daily use of one of the many good quality soluble vitamins will stop the occurrence.
Published Joseph Gallea 15th July 2005