We frequently see that owners are going out of their way to get "full spectrum" lighting for their birds. In doing so they pay an additional cost and may get little to no benefits.
If you want lighting to increase the daylight hours for breeding - I would guess any light would work. I use to work with horses and increased their "daylight" time by just plain old fluorescent tubes (about $1 a 4 foot tube. I have seen bird breeders say they use the same. Certainly before these lights were "invented" many use tubes or incandescent or other bulbs.
If you want to get "sunlight" to your birds to produce vitamin D, I am not sure that a bird competely covered with feathers is going to be helped. We know humans that spend time in the sun do not get the benefits if their body is completely covered by clothes. Besides do we even know that a bird needs this vitamin. They may not even need the sunlight but do need light for their circadian cycles.
I do not believe it is the "color" of light but just the fact of light that looks like daytime to the animals. Certainly "Daylight" fluorescent meets this requirement.
I tthink this is pretty much verified by the following at least in humans and I doubt there is any real scientific studies for birds:
The non-profit, Lighting Research Center, a group of utility companies, experts and government agencies, established the National Lighting Product Information Program (NLPIP) to provide objective information about the effectiveness of different lighting systems. According to the NLPIP, full-spectrum light does not provide any improved benefits over similar light systems:
“Full-spectrum light sources will not provide better health than most other electric light sources. Recent research has shown that human daily activities are strongly influenced by the solar light/dark cycle. The most notable of these daily, or circadian, cycles is the sleep/wake cycle; but other activities including mental awareness, mood, and perhaps even the effectiveness of the immune system go through regular daily patterns. Light is the most important environmental stimulus for regulating these circadian cycles and synchronizing them to the solar day. Short wavelength (blue) light is particularly effective at regulating the circadian system; long wavelength (red) light is apparently inconsequential to the circadian system. Thus, to maximize efficiency in affecting the circadian system, a light source should not mimic a full spectrum, but instead should maximize only short wavelengths. Even if a full-spectrum light source includes short wavelength light in its spectrum, it will not necessarily ensure proper circadian regulation because, in addition, the proper intensity, timing and duration of the light exposure are all equally important for satisfactory circadian regulation (Rea et. al, 2002).