so far so good on the electric bill but we are just getting started on colder weather, i think we are good for ventilation as there is no condensation in the coop or on the windows
we left an opening at the top of the run ,didn't completely seal it it plastic, and in the coop there is to vents...
HI we are new to having chickens , we got ours earlier this yr we have enclosed the coop with some heavy plastic around the run part to make it wind proof. My hubby was worried about his girls so he ended up putting in a ceramic barrel heater at night we close the door and it keeps it at 40 deg...