I just went out to check my quail and one of my 8 coturnix quail was dead. there was a quarter size hole right up the bum and all of the guts were gone. I have been having mice in my chicken feed but they were just field mice. The cage is about 5 feet off the ground and at least 2.5 feet away from anything the mice would be able to climb up and i the cage is in my garage that is closed up. what could it be. also my cage is made up of 1 sqaure sides.