I'm sorry that she's not improving:(
I think you are doing what you can for her.
Only you can determine if she's had enough and it's time to let her go. If you do, then getting a necropsy through your state lab will give you some answers. https://www.metzerfarms.com/poultry-labs.html
I would give the Tylan50 at 0.25ml per pound of weight given orally 3 times a day for 5 days in a row.
Panacur dose is 0.25ml per pound of weight given orally once a day for 5 days in a row.
It won't hurt to use the Corid, but if the fecal float didn't show anything, then not sure if you...
Any lice or mites?
Crop emptying?
When did she last lay an egg?
Did you finish the 5 day course of Tylan50? What dose and how many times a day?
Wormed with Panacur? What dose?
A gram stain may be helpful or a different antibiotic. Baytril is banned for use in poultry, but sometimes a vet...