No need to worry dolfi. They are not used to it that cold I know...but one night like that will not hurt them. Put some bag balm on their combs if you wish. Make sure they are well ventilated, but out of drafts, and kept dry through the night. 30's are pretty easy for chickens to handle.I'm in Florida and temperature tonight are going to be on the 30's. Should I be worried. They have an open run which I added wood boards to make a L against the wind and put three red heat lamps in