How old is she? What do you feed her normally? How's her poop? Could you post some pictures of her and her feet? Have you added any new birds recently?
She's a year old. I feed her fruits and veggies in the morning, layer crumble is always available, another sunflower and corn mixture on the ground at dusk as a snack, plenty of clean fresh water everywhere. Everything is organic. Coop is super clean, as we are still in warm weather, and we burn the hay poop every 2 weeks. Her poop is runny (it was awful with the antibiotic...we were both getting baths daily after breakfast) and is green due to the fact that I am feeding her spinach and avocado and banana smoothies. She is starting to snap at bugs again when she is on the ground. She actually caught a gnat flying around her head (we cheered). No new birds, and I've raised all 22 birds by hand since 2 days old. All of them very spoiled and tame.
This particular barred rock hen (Squeaker) has a sister, Z. They look different. Z looks like a regular ole chicken. Squeaker has always looked like her head was wider, flatter, if you will. Her whole body has always looked like somebody stepped on her and she spread out. We use to joke that she had special needs, but she may actually be disabled.
I will post pictures of her feet tomorrow. I just put on the shoes and want her toes to stay straight for a night.
Would this type of showing wait until now for a break down in the immunity to show it's ugly head? I don't want to put her to sleep. She's very much a pet in the house. She's the chicken that runs to us when the car pulls in the driveway.