I've had raccoons get my birds before and not leave a trace of evidence...a few small drops or smears of blood is all that was left...they ate the whole bird, feathers and all...I swore up and down that a two-legged predator had gotten them, until I found a tiny piece of skull. They pulled them through the wire a piece at a time.two sides were plywood. two sides were chicken wire and mesh. the bottom was just chicken wire so poop could fall through. the roof was chicken wire and mesh. i had four birds yesterday.
upon further inspection some disturbing details have come up. there are two small smears of fresh blood on the feeder and waterer. the dirt underneath the coop looks like it could've been disturbed recently. the roof, which was always been less stable than the rest of the coop, has always had a slight gap in it. it's not nearly big enough for a quail to get out of, but it is pliable, and it ricochets back in place when moved. a raccoon or a housecat could have dragged the birds through the roof gap if they were particularly smart.
it seems like a stretch, but it's the best explanation i have. as for humans and theft, i doubt it, because the only neighbor who knew i had quail was my next door neighbor, who is very friendly and helped me try to find an escaped quail once.
this is especially jarring because i have recently suffered the loss of two very special birds to me and i am still mourning. i have no idea how to even begin to process this.
These birds where in a 1" by 1/2" welded wire enclosure with 1/2" HC flooring. No latches were unlocked.