I hope someone can help me with this. We have a RIR hen 2.5 years old. Of late she has been lethargic and sits around with her head and neck pulled tight to her body and looks as if her feathers are puffed out more than usual. She will eat and follows the other chickens around the yard but lags behind and just stands around not really foraging. Today I noticed she is having bright yellow watery diarrhea. Any ideas what this could be?? Thank you.