If they're likely to feel crowded or otherwise grumpy, and the coop is already pretty light and bright (lots of windows, located in full sun), and you live somewhere with decent daylength in winter, I think a reasonable case can be made for at least a medium color rather than white.
OTOH if your chickens have plenty of room and no elevated risks for picking, and/or the coop is in a part shaded area or has not got all the window area in the world, and/or you have really short winter days and care about winter egg production but don't want to run a lightbulb, then you are probably better off with white or near-white.
I am not aware of any research on how color affects chicken behavior. I do not think that painting the walls red would be at all similar to having a red lamp running, or red lenses ont he chickens eyes -- the red lamp etc work because a) they make overall light dimmer, and b) they make wounds look black rather than attractively bloody red. But, I don't know anyone with a red-painted coop interior to test the theory either
Frankly I think whatever you can get from the mistint box, or someone's basement, is your best bet. There are lots more important things to worry about, that are well documented to affect chicken behavior (like giving them extra room), I wouldn't get hung up on decor
Good luck, have fun,
Pat
OTOH if your chickens have plenty of room and no elevated risks for picking, and/or the coop is in a part shaded area or has not got all the window area in the world, and/or you have really short winter days and care about winter egg production but don't want to run a lightbulb, then you are probably better off with white or near-white.
I am not aware of any research on how color affects chicken behavior. I do not think that painting the walls red would be at all similar to having a red lamp running, or red lenses ont he chickens eyes -- the red lamp etc work because a) they make overall light dimmer, and b) they make wounds look black rather than attractively bloody red. But, I don't know anyone with a red-painted coop interior to test the theory either

Frankly I think whatever you can get from the mistint box, or someone's basement, is your best bet. There are lots more important things to worry about, that are well documented to affect chicken behavior (like giving them extra room), I wouldn't get hung up on decor

Good luck, have fun,
Pat