Seeing the picture that you attached, your hen is definitely sick! When a chicken is ruffled, standing alone, tail and wings drooped, head down and eyes closed, she is quite sick. Chickens tend to hide illnesses as long as possible, so by the time you see these symptoms, they are well into advanced stages of disease. If you can, you might want to take her to an avian vet, as there are a number of illnesses that these symptoms are associated with. If you are not able to take her to an avian vet, perhaps you could get a fecal sample and take it to any vet for analysis. If it is coccidiosis, try to treat her with Ivomec or some black walnut hull extract which you would give her twice a day. I wish you good luck with this, and hope your hen gets better with treatment.
Update on Gloria:
We had 2 days of good weather, last Thursday and Friday. In which Gloria ate a whole egg that was laid in the coop, each day!! Now I don’t know if one of the other hens laid it and it cracked or if she started pecking at it, but the whole egg was consumed. The nesting boxes are clean, dry, and warm, and I even have a spa blend in there for them, so it was weird that they laid the eggs in the coop and not the nesting boxes. None of the other hens are eating the eggs or exhibiting signs of illness.
Anyways, during these 2 days of warm weather she acted fine. She walked fine, seemed happy, she was eating and drinking water, no diarrhea that I could see. Then when the weather turned cloudy and our area is gearing up for rain and thunderstorms from Monday to Thursday, she started acting “sick again”. Her feathers are fluffed like she’s trying to stay warm, tailed tucked, shoulders hunched, eyes closed, she even twisted her head around to put in her feathers, closed her eyes to nap here and there. She switches placing in the roost almost every night so I’m trying to track her nightly poop.
I will call my vet to see if they can analyze her poop.
I also was able to pick her up last night and felt under her fluffy feathers. I thought I felt an egg but wasn’t sure. I went to bed very disheartened. This morning I had 4 eggs in the nesting boxes so I started picking up my girls that I thought had laid their eggs and even the one that I think doesn’t lay. All but one was soft and squishy. I felt Gloria again but although she was firmer than than the other girls I didn’t feel an egg. I also don’t see diarrhea in their pen or where she’s been at night.
What scares me the most “Chickens tend to hide illnesses as long as possible, so by the time you see these symptoms, they are well into advanced stages of disease.”
I haven’t seen or heard of the Ivomec or some black walnut hull extract but need to confirm what she has before I start giving her stuff. I will put those remedies in my book of knowledge though, thank you!