I live in Mn and we have been having some extreme cold temps. We have a ceramic coop heater set at 40-50. We feed and change water daily. They have stopped laying eggs, not eating like before and have noticed some feather loss on one in particular. The weather has been in the negatives and have been keeping them in the coop for most of the winter didn't know if that was a problem. Very new to chickens was wondering if this is normal or something I should be concerned about.