My banty has a mystery ailment

[callmecordelia2]

For a few weeks now, my 18 month old barred rock bantam hen has been opening her beak wide a lot; it looks like a yawn. Otherwise, her behavior was normal until the past few days. She often sits with her legs splayed, her chest on the ground and head drooping. She is not injured and walks fine; it's just a weird sitting posture she has developed. Her eyes are droopy and often closed; no discharge or anything. Sometimes she sits out in the yard like this off on her own while the other 3 hens scratch and eat. I have a book on chicken health but could not find these symptoms listed. Any advice? I'm worried she is dying.

 

[kazoo1111]

Does she sleep a lot?

 

[callmecordelia2]

She does seem to sleep a lot. When the others are out scratching and eating, she is sometimes just dozing off.