Bumping this to see if we can get an answer to Kickin's question.
My 8 are about 7 weeks old & seem to do ok down to about 30. Last night when I went out to check on them, it was below 30 in the uninsulated coop & they looked miserable. There were ice chips in the water. We have a heat lamp, but it doesn't seem to help much unless they're right under it, and they don't all fit. I had my son hang a small space heater out there & we turned it on to the lowest setting just to keep it above freezing. Now I'm worrying if I should have just let them start adjusting. It doesn't often get below 20 at night where we live, so if they could get adjusted to that, they'll be great, but to me they're just babies. Our roo still doesn't have all his feathers.
I've been reading the 'cold' threads, but it seems most of them are about chickens that are pretty much full grown.
Thanks!