We have a very vibrant flock of 20 birds. 17 hens, 3 roos (2 living on borrowed time waiting for a dinner invite). Mixed Barred Rocks and SL Wyandottes. Every night, one of our hens goes missing. She's back every morning before the coops opened up and occasionally shows up to mingle with the flock as we've counted 20 during the day. We've done extensive searches in the evening and cannot find her. All the other birds act normally snuggling together against the cold but the one is missing every night. What gives? Is she hiding/brooding eggs somewhere or what? Am concerned she will run afoul of a fox or coon one night out by herself.