Yep in my opinion they do. Well maybe not blues exactly but they are much happier, livelier, curious, active and enthusiastic when it's sunny.
A full spectrum Phillips tube lighting system (hanging shop light, 2 bulbs CRI > 94 kelvin >5000, electronic ballast
only and 2-4 feet away OVER HEAD not on the side)....will help over the winter.
Enthusiastic also pertains to pesky habits like nipping their par amour.
