There are mixed feelings on Full Spectrum Lighting.
There is also a lot of confusion over what ones to use.
While I have No Doubt, all birds need good light, for many reasons. I worry about high intensity bulbs, and feel low energy ones may not be good enough.
I have read that there seems to be an increase in eye cataracts in recent times and it could be indicative of the use of F.S.L.
The other trouble is that when talking to a supplier they will tell you these are what you need! But this may not be the case.
If I have confused you, I am sorry.
Scott Echols did discuss lighting or sunlight on his Nutrition for pets Facebook page.
This is the link to his page, but you will have to search for the item. Sorry I am not a facebook person and struggle to find my way around.
Lighting / Sunlight gets very complicated.
My own feelings: Though glass blocks most UVB rays, which are the ones you want.
If they are getting good light and diet, they should do all right without adding extra lighting.
But this all changes if you live in places where you do not get intense light or your bird room is away from direct sunlight.