Usually chickens with coccidiosis won’t eat due to the pain. If you do treat with Corid, make sure there are no vitamins given, and some electrolytes have those. Nothing should be given with Corid, so they drink enough of the treated water. Keep us updated on how she is doing.
She has a little frostbite on her comb, and minimal on her wattles. I would still keep trying to get her to eat, keep up the probiotics, and try a little tuna or ground meat bits. Once she starts eating better, cut back to mostly chicken feed. You have done most things I would have thought of so...
What does her crop feel like? Empty, full, firm, doughy, or puffy soft? Can you recheck it in early morning before she eats or drinks anything. The green lookups like she is not eating much. Has she ever laid eggs, and were they normal?