One of our guinea hens has spent a lot of time hunched up on the floor for the last week or two, when it got really cold here. My dad picked her up today, and she was really lethargic, cold, and lightweight. She wouldn't eat, either. She is probably about 4-5 years old, but has seemed healthy until now. Another guinea hen, one I actually tamed, is also really lightweight. She is slow by nature, but normally really heavy. Now she barely weighs a few pounds. It has been in the single digits here, plus snowy, so they can't get outside. All the rest seem healthy, but we haven't been able to catch them and feel their weights. Has anyone ever experienced this before, or have any ideas as to what might be going on?