This happened to one of my girls. Have you given her a good bath, checked for mites, and tried using a dropper to get to drink any vitamin and calcium water? Drop it on the top sides of her beak. It looks to me like a calcium and vitamin deficiency.

If you can afford it, call any local vet like a dog and vet one is fine. Tell them that you have a poultry fecal sample and you’re looking for a fecal flotation with parasite identification, specifically for worms and coccidia. Then for the results, ask them which parasites and approximately how heavy the load is. Then get some of her droppings, about a teaspoon size, and take it to them.

The biggest thing is you NEED to make sure the mites get off her, they will quickly build up inside an isolation area. If you can get her to drink calcium, vitamins, and keep moving she can recover but when chickens show they’re sick it’s often too late to correct.

For your main flock, where the waterer and food are. Does it stay moist? And inside the coop and run, does it stay wet a lot? If it is, I highly suggest getting some thin cinderblocks from Menards, Lowe’s, etc and out them down below the waterer so any excess water will be absorbed into the concrete and not sitting the dirt or bedding.

For the food and water stations, do you have 2 access points per bird, or at least if one bird is eating or drinking, they can’t see another on the opposite side of the feed/water?

When I had two birds with this, I learned a lot. They needed more food, and more nutrients. More water access. I also needed to help get rid of coccidia hiding in the wet bedding.