I am so sorry! I have gotten up in the middle of the night in a panic remembering that I had not closed them in myself. A couple of times I've gone out to feed in the morning and would see them already in the yard! Thank goodness I have not had a disaster. Sometimes you just get so busy.
I was awakened to the chicken scream & knew right away what happened...I ran out with a flashlight & they were all spooked but It was too dark to see anything & I didn't realize she was missing till daylight!!
So sorry for your loss. While I understand that this incident was able to occur because of the open door, I would suggest double checking your security because it is very likely this predator will return and, having had one good meal, will be even more determined and likely to test each and every level of security you may have employed. Think like a hungry, determined predator and really look at each and every place you might try to get in and really test those areas to see if they hold up as well as they are intended to.
We are suspecting a coyote as one has been roaming the area lately and since there were no feathers inside the pen or coop I think she ran out when it spooked her and that's when it got her....we never saw any blood or anything but feathers...and whatever it was it jumped a 6ft chain link fence escaping taking her with him!!!
The hen we lost was the one in the cage, I'm wondering what breed she was as we've attempted to sell out & everyone wants 1 or 2 but I won't sell unless they take all w/coop & accessories. If I can't sell I'd like to replace the one we lost with a couple more of the same breed..