And that is exactly why I have a cage without any lights on. My guess is that the snake in the cage with no lights does exactly the same or better than the snake with the full spectrum bulb
After this I am going to try the same thing with a diurnal snake/reptile.
I do believe that a diurnal species would benefit much more from a full spectrum bulb. But with that being said I also feel that all living things benefit from natural sun light.