Security question and random death question

[dbc00per]

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.

 

[LaurelRidgeDreams]

Is this the temperature inside of the garage? Are the birds panting?

 

[Egghead_Jr]

What's the temperature inside the garage? It should be cooler in there than outside so letting the door open all day is self defeating. They should have a small door access from coop to outside available to them when ranging. It sounds as though you've enough air flow for four birds.

Believe it or not we had a random death last week with one of our 15 week pullets. No sign of predator, plenty water, temp only 80 F and I saw her walking about fine just a few hours earlier. Then went out toward dusk to see her in her coop lifeless on the floor. It was sudden whatever it was, gave her enough time to walk to coop then die short period as we were home and I take smoke breaks on the back deck watching them.

 

[allpeepedout]

Do you have good ventilation to night air? Previous poster's question about panting is spot-on. Are they comfortable? Have shade in day?

Although I have eave/gable ventilation to the outdoors around two sides of my coop, which is built into the corner of a shed, it stays way too hot inside on these summer nights, when the heat index can still be in the 90's. (Planned to add more ventilation but it's a trade-off with security issues and wanting to keep crowing noise contained from neighbors.) I hung a fan in the gable vent to pull in a nice stream of cool nightime air.