In native environments, most of the Vitamin D intake of birds is through diet. In the 1960's, Dr. John Ott discovered that sources of light lacking in the upper and lower ranges of the spectrum could induce nervousness, fatigue, headache, disruption of sleep patterns, etc. By adding long wave ultraviolet to the lamp output of fluorescent devices, these conditions could be remedied. This gave birth to the first set of full spectrum lamps. Since this time, major advances have been made in the technology of fluorescent light manufacture.
Many companies now produce devices which provide a more natural light.
Reptile keepers have long needed a source of UVB to keep their animals healthy. Reptiles must have these wavelengths, or suffer from Vitamin D deficiency. Recognizing that a real market exists for specialty devices, many manufacturers began production of Full Spectrum devices which contain quantities of UVB along with UVA and balanced visible light. Special use, special prices for production. Taken together, we see that the step Nazi doctrine of full spectrum holds little credence for the practicing aviculturists.