Can I leave the coop door open all night?

[JackE]

Check out the coop link below. The front of the coop is WIDE OPEN year round. The other windows are opened up in the warmer months. The windows are closed when the temps get below 40. Coops like this were used back in the day up through Canada. Old, but proven, chicken technology.
Jack

 

[Chickety Charcoal]

You will be fine.

I also have a secure run and I often leave the door to it open all night. I have two big windows on either side of the coop, one being right near their roost, and the only time I close them is during very heavy rainfall & wind (hurricane). It gets down into the 20's here in winter and they are fine. Most of the common chicken breeds are winter hardy. A night in the 50's would be pleasant for them.

A different issue I have had with the coop door being open is mice. They manage to find the tiniest space in the run to slip through and will be very persistent in getting to any leftover feed. Like mini ninjas they hide their entrance and exit tunnels under rocks and plants. It's only after very close inspection that I can find them. They are pretty harmless though, as they don't bother the birds they just want the feed.