We are still getting down into the 40s, I keep a (red) light on. I've noticed this time that my chicks (9 of the 12) are HUGE. I don't think I've treated them any differently than the McMurray chicks from last year (but then I used a white light) but these things eat like it's going out of style, drink like crazy and poop everywhere and at 2.5 weeks they look like they are almost fully feathered and they can fly!!!
Only the marans and one CA leghorn are still smaller and have bits of fuzz. The other leghorns, the ameraucanas and the sussex are just huge.