We all want to feed our birds (and ourselves) the nutritional right combination of foods to be healthy and happy. I know people that try to provide the exact composition of foods for their birds needs. But these needs vary, depending on such things as species, season, genetics, and environment. Even two birds of the same species--having come from different parents (genetics), having been exposed to different environments, having been feed an insufficient diet before they came to you and probably many other unknown factors--might have different nutritional needs. Figuring out the best diet (according to current science) for a species can be rather difficult. Our scientists are constantly finding new nutrition in fresh, natural foods, which are important for our well-being. How many more will they find over the next years?
Using fresh vegetables, fruits, seeds, nuts and pellets and trying to combine the currently known nutrition to create a perfect food for your birds is very wise, as long as you use natural food. Even then, feeding all the time foods that provide the same nutrition is not such a good idea. The good thing is that birds usually pick out what they need at any given time, if variety is provided. So, they can help us there, if we pay attention.
Another important thing is not to underestimate the intelligence of the body and its functions. As long as it gets a minimal amount of its needs met, it can adjust its lack of some nutrition and sometimes even heal itself. For example, when we provide a food with water-soluble vitamins in a natural form, the body absorbs what it needs at that time and the unneeded amount will be eliminated. We (and our birds) do not absorb all the vitamin C of an orange or any other food when we eat it. Our wonderful, smart body takes what it needs and the rest is passed on back to the environment.
It even gets better, when it comes to fat soluble vitamins, like A, K and D, which are produced by the body itself, under the right conditions. For example if you feed foods with beta carotene, again, the needed amount will be turned into vitamin A. If a bird (or a human) is exposed to sunlight or full spectrum light its body will be able to produce the needed vitamin D. Taking care of the fat soluble vitamins this way we don’t run into the risk of vitamin toxicity.
So, instead of counting vitamins and minerals, we should just provide a variety of foods in moderation. Birds that are used to eating many different foods usually can make the right choice for their momentary needs.
A little personal story about cravings and needs:I was for a while vegetarian, but did not do very well on this diet. So, I started eating some fish and chicken a few times a week. Though I was eating a balanced organic diet, I was having some health issues. At the same time I started having this craving for dark red meat. Something I normally don’t like taste-wise. I finally ended up at a Chinese doctor. He told me after a rather short survey, that I was anemic and needed to eat more red meat. So, after getting some acupuncture, Chinese herbs and eating more red meat, I feel better then I have felt for many years.