VITAMIN D IN PARROT DIETUnlocks the Calcium in the Body and Moreby Sally Blanchard
Basic information: Vitamin D3 is necessary for calcium to be utilized by the body. This nutrient is not just a vitamin but it acts as a hormone in the regulation of bone health, muscle health, immune response, regulation of insulin and blood sugar, and regulation of calcium and phosphorus metabolism. Unfortunately, this nutrient is not really available in most foods that we feed our parrots, including such foods as salmon, sardines, shrimp, cod, cow's milk, and eggs. Feeding some hard-boiled egg, some fish, and plain yogurt made from milk, or white low salt white cheese can be fed to provide this essential vitamin. Both yogurt and white cheese lack the lactose that parrots have trouble digesting.
Placing parrots outside in a safe, secure, and supervised cage or aviary with plentiful water during nice weather can really make a difference. Make sure the parrots have a chance to find shade in part of the cage. Too bright and hot a sun can both seriously overheat and dehydrate them.
However, with daily exposure to full-spectrum UV lighting either through sunlight or full-spectrum lights, parrots can synthesize vitamin D. The glass that is normally in windows and doors blocks UV light so full-spectrum lighting is recommended in the room where the bird lives and/or spends most of his time especially winter when they can't spend time outdoors.
A few readers might be interested in this information: Why does window glass block UV-lighting? Evidently, during WWII the gunners on the top of the bombers were experiencing severe sunburns from constant direct exposure to sunlight. So during the war, they started to make all window glass so that it blocked UV light. Good or bad, that's the way it is.