Chicken's comb is down and tailfeathers down

[indigoisland]

We have several Production Red hens. About 2 months ago, one of them, now called "Goody", started acting lethargic, wouldn't come out of the coop, sitting on the floor, tailfeathers are low, instead of "upwards" and "bushy", and her comb is bent down. This has lasted all this time. She has not gotten worse, and has improved some. She will venture out of the coop and get out and about, but still sticks very close to home. We thought maybe she had been bitten by something. Anyone have any clues?? She still eats and drinks just fine. Our coop has a high roosting rafter, and she doesn't roost high anymore. We have high laying boxes and low laying boxes - she sleeps in one of the low laying boxes.
Thanks,
Bahamas Chicken Farmers

 

[Eggcessive]

Check her for lice and mites. Worm her with a good wormer like Valbazen or Safegard liquid goat wormer. Make sure she is getting a good layer feed with at least 16 % protein. A bit of plain yogurt twice a week or some probiotics might help. How do her poops look?