Today I found my flock decimated! I lost 6 of 9 standard hens, and 11 of 12 bantams. 9 ducks are all okay. Our enclosure is an old animal corral, 35 feet by 150 feet with 7 foot fencing. Then there is a 6 foot wide "aisle way" running the length of the pen inside the main gate, to keep any of them from rushing the gate and escaping, and to allow us to split the yard later if we get different kinds of birds. Chicken wire is wrapped around bottom, and folded down on the inside, and tin folded and buried on the outside to discourage any digging predators. I thought we had so much redundancy that they were safe. Walking around the enclosure tonight I can only find this small tunnel sized hole. What could have done this, and how do I keep it from happening again? I have everyone locked in the grow out pen for tonight. It is a 6x10 chain link dog kennel. Hopefully that will keep them safe for tonight.