bummer..it does sound like they are cold.
we just had the same cold frount and now a week of warm weather to fortify
Its not only been cold, but damp, and I think thats the diff...I added 4 ml plastic sheeting around the interior of the coop to keep out drafts, checked for damp places, and have another bag of pine chips to add insulation.
My chickens free range all day, so they are exposed to all types of weather, I think damp and drafts are the worst problems, that and no sun....
Heres hoping winter isnt as bad this year, but I don't want to loose chickens to the cold either.