Hi Ren and welcome! I did not know that about quail. So they’re more aggressive to each other than chickens, ducks, turkeys, or geese are? Wow. But like you said, probably some kind of weasel… did you find any openings where it may have gotten in the coop? They can fit through a space the size of a quarter I’m also amazed at how self-sufficient you are. That is so fantastic good for you. Keep it up.!!