Well, I noticed that my girls go to bed about a half an hour before the so called "bright" full spectrum lights turn out.  By the time the full spectrum lights go out, and only the red lights are on-there is usually only one persistent chicken still out scratching in the bedding for those last few treats that didn't get eaten earlier.  (The same one every time, our little banty english game hen.)  It's quite obvious to me that it doesn't 
matter if the "bright" lights (and all of the lights) were to go out all at once, they have 
adapted themselves to getting on the roost about a half hour before the main lights go out, unless someone happens to go in there and give them some treats much later than their usual bedtime snack which I normally give them about an hour and a half before bed.  Then I will occassionally find a number of them not getting ready, as they just have to get that last little treat eaten up. 
I think too many people make 
suppositions without actual knowledge, just as a child who has never eaten a particular food but doesn't like it, because his friend doesn't like that food, and guess what-
that child doesn't like it even though he never tried, it but 
his friend doesn't like it, so he won't even 
try it!!! 
  I can't stand picky kids-or their picky parents, for that matter!!!  (A pet peeve of mine! 
 ) When picky kids come over, they eat what I make, or they don't eat at all!!! 
Yep, many people will disagree, even though other people's actual experience prove things quite differently for something that they may have never even tried themselves, or even if they did, perhaps they didn't try it long enough for their chickens to adapt to something different than what they are used to.   
  I dunno, what's the world comin' to, anyway?!!! 
Edited to add: I really think there is a whole 
world of difference between a huge brilliantly bright mag light shining in a chicken's eyes than full spectrum bulbs.  I really can't imagine ever using a light that bright-I'm 
sure my girls would have been very upset, and decided the sun was awfully bright that morning, as well!! 
 Sometimes comparing apples to oranges can be totally two different types of fruits!