Post a boatload of pictures of her, standing; walking; a few images highlighting her posture when standing and when 'resting'; Entire face from front, prefer a good shot of both eyes and nares (nostrils); full face, side view paying close attention to focus on the eyes (2 pictures, one of each eye, including beak and nares is a plus);picture of her from behind, close attention paid to vent area and surrounding feathers. Pictures of her feet and legs, both tops and bottoms. picture of the inside of her mouth. Picture(s) of her poop can offer a ton of information.
All of these pictures will help someone with a practiced eye spot issues that may go unnoticed otherwise.
Gently pinch her breast bone, is she skinny? Palpate her abdomen, is it squishy? Gently massage her crop, once in the morning before she's offered food or water, again at bedtime as you put her to bed for the night (should be flat in the morning and fat at night).
Has she ever laid an egg? If so, when was her last egg laid (one that you KNOW is hers)?
Does she smell sour or yeasty on either front end or back end of her?
Any time a bird is not acting like themselves, is a time for worry; birds HIDE their illness, often to the point of no return.
When was the last time your flock has been treated for cocci? Cocci are a one-celled parasite that is found in every single square inch of soil in the world. Their eggs and the parasite themselves are particularly easy for your flock to ingest after rain, as they float to the surface. All chickens have a cocci burden, but when a bird has a compromised immune system due to underlying illness or injury, the opportunistic parasite strikes hardest.
If she were my girl, I'd put her (and your entire flock) on Amprolium (Corid) to reduce the cocci burden in your flock. Amprolium mimics the B-vitamin that cocci eat, so do not offer b-vitamin supplements while treating for cocci but DO offer them after the course of treatment is complete.
I will keep you and your feathered family in my prayers.
