Just found one of my BO pullets with her head on the ground. She can still lift her head, but has a hard time keeping it up. This is her only symptom, and she was happy and active last night. My hens get layer crumble, kitchen treats, BOSS, whey (from the goats' milk), and ACV in their water. They free-range during the day and are locked up in a coop at night. No sign of injury, and nobody else is sick. I've brought her into the house and am awaiting any ideas from this wonderful, experienced group of chicken lovers. Thanks!