Well, I think we are a little closer to what ails her. I'd stop the cracked seed/corn. Stick to a layer or all flock with oyster on the side.
If it were me.... i'd give her some crushed calcium on a small piece of fruit or a little bit oats. Tums, or people calcium works. Then I'd give her a warm soak with Epsom salt for as close to 20 minutes as I could get, gently massaging her under belly. Feel if it is hard or swollen.
I'd also put a gloved small finger coated with coco oil or similar GENTLY up her vent 2" to feel for an egg.