In addition to a lowered immune system, it has been our experience that the blue mutation has a lowered ability to process pro vitamin A. Vitamin A is essential for growth, healthy skin, mucous membranes, and good vision. Vitamin A deficiency effects the epithelial lining membranes of the respiratory, alimentary, and reproductive tracts. This is why we often see sinus & respiratory infections in birds with a vitamin A deficiency.
Mucous membranes are the bodies first defense against bacteria. When a vitamin A DEFICIENCY is present, the lack of healthy mucous membranes allows infection to gain entry into the body.
Vitamin A is stored in the liver and found only in animal tissue, though carotene is converted by the body into vitamin A from plant sources. Therefore, a diet high in vitamin A goes a long way to keeping them healthy (or healthier depending on genome).
Spirulina is one food that contains relatively high levels of vitamin A along with trace amounts of necessary iodine (which aids the thyroid – the thyroid drives many organs and bodily functions), is easily fed to the birds, and easily recognizable in the fecal samples (to confirm they are getting it into their system). It doesn’t take much to really help so is a cost effective means of delivering the vitamin. Merely sprinkling it over their food as if you were salting your own food is usually enough when starting with relatively healthy birds.