I live in Utah. I will be putting the finishing touches on my new coop tomorrow and I'd like to move my chicks out there. They are 5 1/2 weeks old and it looks like they have all of their feathers. Nights right now are still down in the low 40s (although Sunday is supposed to get back down to mid-30's, but then back up to 40s after that). Too cold for them? I have a heat lamp I suppose I could move out with them. Any advice is appreciated.