Hi, I know people say that chickens should be fine in really cold temperatures 'as long as the coop has no drafts'. Well, in our coop, the whole front is open, and covered in hardware cloth. Well, last night it was 39 degrees...and we have six week old chicks. They are fully feathered...but they LOOKED really cold. And it was windy! So do you think they need a heat lamp or something like that? Or am I just worrying to much? Thanks!