Last week I noticed my adult hen (five years old) hunched over in the barn away from the flock. I immediately brought her inside to examine her. No signs of trauma. Her feathers look fine, cone is nice and red and her eyes are clean. No crusting on her vent and it looked fine as well.She seemed alert, but would not eat or drink. I gave her a spa treatment; a warm soak in water mixed with about a half cup of Epsom salt and a good dose of olive oil. I dried her well with the hairdryer (which she loved) and left her in a dog crate inside. The next day she still looked fine, but the food and water I'd left for her were untouched and she had not pooped. I gave her another spa treatment and the olive oil. She seemed fine otherwise ... alert and in no distress. I left her isolated in the coop that day and away from the flock. It's been this way all week. It was chilly last night so I kept her inside, after her spa treatment. Still not eating or drinking. This morning I gave her another liberal dose of oil and offered her bread, which she ate after I gently pried her beak open a bit. I didn't give her too much ... maybe a heaping teaspoon. I also made her drink water. She immediately pooped. I put her back into the coop, isolated from the flock (my chickens are free range, but they do roost in the coop at night). The other hens are not picking on her, but since she's been sick I bring her in at night to sleep in the dog crate. She hasn't laid any eggs since the onset of this strange illness and seems to be feeling okay. She is not molting. I feed a grain mix ... not a medicated or laying pellet and they eat bugs. All the other chickens are fine. I don't know what could be wrong with her. Does anyone have any advise. This is my favorite chicken ... Thank you.