I've read and read and read on here that they should be fine, but I worry!! They are a few days short of 8 weeks and are fully feathered, with the exception of a few of the silkies....they still have a bit of fluff on thier heads. Thier coop has roosts and copius amounts of hay for bedding, and they are very good about cuddling with each other. But it's supposed to be 35 tonight. I worried a ton about the big birds when it got cold, and they have been fine.....dunno why the little ones have me so worked up.