Saturday night we had a lethargic hen. She didn't want to move, her comb was folded and balance was off. By morning she was gone. I did a necropsy on her yesterday and the only thing I noticed was an inflamed deep yellow liver. This morning I found another one dead, almost suspended in time on a perch in front of a nesting bucket. Stiff as a board. We have (or had) an extremely healthy flock. No one has mites or lice. I have 150 laying hens and 150 3 week old chicks in the same barn. I'm now very concerned about an epidemic. Help!!