Hello, I am a first time chicken parent who received month old pullets from Murray McMurray a few weeks ago. They are now 6-8 weeks old and our chicken house and run will finally be done tomorrow, so they are moving outside! We have a cuckoo marans, barred rocks, SLW, and Easter Eggers. The EE are smaller and still have some downy looking feathers under their wings. I do have a heat lamp about 3 feet above their brooder at night (they have been loose in my spare room / tack room 12 hours a day) as that room has no heat and they still pile up under it. It has been 39-40 degrees here at night and I will put a heat lamp 3 feet off the floor in the center of their chicken house. Will they likely be ok? Their current bedroom is probably about 50 degrees at night.