Every once in a while a customers calls me or sends me an email, asking the percentage of vitamin A or D 
in our TOP pellets for parrots. They want to do it right and try to count the vitamins and minerals in their parrot food. They first are shocked when I tell them there are no vitamin A and/or D in our TOP pellets or in any natural food. These are both fat-soluble vitamins, which are produced by the body when given the right condition. The vitamin A is taken in from beta-carotene, which is found in many foods like carrots, squash, mangos and most green vegetables. The body converts the beta-carotene into vitamin A. The good thing is that, from these foods the body can take the amount it needs and turn it into vitamin A. So, there is no danger of getting too much of the vitamin. If you look at the ingredients of TOP pellets, you will find organic carrot powder, organic spinach powder and organic alfalfa leafs, which are all high in beta-carotene.
To produce vitamin D the body needs the exposure to sunlight, specifically ultraviolet B radiation. For a long time it was believed full spectrum light would provide this. But now there are different opinions about it. I still have full spectrum lights in my bird room and think they are doing well.There can be situations, when a bird is depleted and it is wise to give a vitamin A or D supplement, after consulting with your veterinarian. But I would not give it on a daily base to a healthy bird.