In answering your question about Full spectrum
lighting, I think that before reading any of my comments that you should first read this;
http://forums.avianavenue.com/index.php ... mp.149742/This is from another forum that I am a member of.
Full spectrum lights can be a good thing but only if you use the right ones these being either the tube type or the compact fluorescent bulbs with a K Temp of 5000 to 5500, a CRI of 94+ and a UVA/B output no greater than 2. These are the specifications as you can't trust the labeling on the package you normally have to look for this information on the base of the bulb or printed on the tube. Because of the risks involved you can not take any part of this for granted.
Now there are many possibilities for why a bird may be deficient in calcium and they should all be considered in relation to the amount of calcium that you provide for your bird. The vitamin deficiency that is found most often in parrots is that of vitamin A, a bird that is deficient in vitamin A is going to be deficient in calcium, even if the bird is actually receiving enough calcium. Then you must also look at the amount of phosphorus and magnesium in the birds diet. Magnesium is required for the bird to use sunlight to manufacture vitamin D-3, but magnesium is also a calcium blocker so although it is needed yo must be careful not too have an excessive amount of magnesium or you will have a deficiency of calcium. Vitamin D- 3 is required for the bird to use the calcium and phosphorus must also be in the correct ratio as too much of it will also result in a calcium deficiency.
The best way to supplement the birds vitamin A levels is through diet by using foods such a broccoli that are rich in this vitamin. Sunlight that is unfiltered is the best way to provide a bird the means to make the vitamin D-3 that it needs. If the temperatures are 50 degrees F. outside with very little wind you can take your bird outside for 10 to 15 minutes without any problem especially if there is a sunny day. You could even do this a couple of times a day at these temperatures. You could also supplement the birds vitamin D-3 levels through a powdered vitamin/ mineral supplement that you sprinkle on the birds moist foods. In this case it sounds like the vet is saying that the birds calcium levels may be low due to not enough vitamin D-3.