Noticed a sick looking hen yesterday and put her in a separate cage last night and she was dead this morning. She was a 4 year old Buckeye hen. Saw her laying in a corner yesterday behind the feed cans, picked her up and she felt real skinny. She might have been their a while - I've had a lot of personal family drama lately so haven't been keeping a real close eye on the birds, just feeding and watering them. I let her walk around a bit and her tail feathers were all downward and she seemed kinda hunched. Laid down pretty quick. Saw her do one runny liquidy greenish/yellow poop. No obvious injuries. This morning she was dead and looked like some mucus (although not a lot) in the airholes on her beak. I didn't see any mucous their last night. All my other birds seem fine. Any thoughts?