I would be concerned about bad drafts more than cold temps. As long as there is good ventilation but NO WIND blowing on them, chickens can handle cold. I know it has been down to -20 in my coop this winter, and my chickens were still scratching around in the litter looking for snacks all day. Also, I am lazy and don't want to get up at O-dark thirty to go out and knock snow off the hoop house when we have those snow storms that dump over a foot of snow overnight.
My neighbors out in Wyoming had a hoop greenhouse and the wind just shredded it and snapped/bent every one of the hoops.
My neighbors out in Wyoming had a hoop greenhouse and the wind just shredded it and snapped/bent every one of the hoops.