Ok my question after a brief summary. I've designed and built a large coop for three chickens and one duck. Within my garage. There is one door on the coop with securable latches, two window type entrances without latches but that close and one section that opens upwards above were they chickens lay their eggs. The entire coop is built sturdy and double layers of closely meshed chicken wire secured everywhere. I live in a suburb of Detroit hence the garage location. My chickens are let out daily,usually about noonish weather permitting. They roam a large yard all day and are put away before dark. Here's is my concern, my fiancé is dead set on now leaving the garage door open at night because she insists it's to hot in the garage and there isn't enough air flow. She also wants the coop open all day so they can get in and out on there own including sometimes going in when they feel the need to lay eggs.. We have on occasion left them out past dusk or later which I'm not comfortable with. We just lost our first chicken today. (door was closed) Not sure why she died. It's cooler than last week, water & food plentiful. Death doesn't seem to be predator related that I can tell. She insists it's the heat. Im not so certain it wasn't just random death or something else. The chicken died last evening between 5pm and 1pm. To my questions, is this as bad of an idea as I think it is. will predators get in even if I think its "fairly" secure. Are random unexplained deaths common. these are our first chickens. So I'm uncertain if I'm worrying to much. It was darn close to 100' all last week. Didn't notice any issues such as heavy panting lethargy, or loss of appetite. it was high 80's mid 90's this week probably no warmer than 80-85 last night. So....summary door open at night a bad idea ???? If cage is fairly secure Could the heat have killed my chicken in the mid 80s when it was 100 all last week with no issues.