I have a 1 year old formerly healthy Americana hen. She has become very lethargic, lost weight and has that peculiar "sick" chicken" smell I've come to know from other seriously ill chickens. She won't eat, won't drink. Don't notice any nasal or ocular discharge, her vent looks good. She just sits there with her eyes closed and her head down. Any suggestions or recommendations? I think she's going to die.