We live outside of Las Cruces, NM. We can get into the teens even had negative a couple of years ago but that happens every 60 years. Normally mid to low 20's. Our chickens insist on roosting on top of the coop which is still protected since the coop is under a car port structure. Will they have enough sense to go inside if it gets too cold? They lay their eggs in the coop and are in and out all day, they have roosting bars in the coop but prefer on top of the flat roof.