Four years is starting to push it for a bird that is bred for heavy production (egg laying). She might be dying as sorry as I am to say that. Nonetheless, we'll try to help.
First and most importantly, make sure she stays hydrated. Nothing else will work if she doesn't get water in her. If you have to hand-water her, do so using a syringe (without the needle) or an eye-dropper following this guide for where to place the dropper in her mouth:
https://www.backyardchickens.com/ar...dications-to-all-poultry-and-waterfowl.73335/
Next, are you sure it's Sour Crop and not Impacted Crop? Sour Crop comes with a foul smell from the bird's mouth area; Impacted Crop usually does not. Here's a quick guide to determine what you're dealing with:
https://www.backyardchickens.com/ar...w-to-know-which-one-youre-dealing-with.73607/
What was she prescribed the Fluconazole for, Sour Crop, Slow Crop, or something else?
What does her diet consist of?
Does she free range, and what does she eat while doing so?
What treats does she get and how often?
When was the last time she passed a stool? Please provide photos of recent stools.
How much is she eating; does it look like she's consuming the same as her flock-mates?
What has the temperature been like in Prescott for the last week or so?
Has she been treated for internal parasites (worms) or treated for Coccidiosis?
Was she vaccinated as a chick against Mareks or other diseases?
Have you checked her for external parasites, paying close attention to the vent, under wings where they meet the body, the feet and legs, and around the neck/head?
2.4 lbs is light for a mature Golden Sex-Linked chicken. If she's Impacted and has developed Sour Crop, getting a pro-biotic into her will help quell the yeast that's building up and causing the smell. For pro-biotic, Greek Yogurt works well mixed with moist feed, as does Rooster Booster and Sav-A-Chick products mixed with Water. If given in Water or in Moist Feed, wait a few minutes, then massage her crop for as much as 5 to 10 minutes to work the therapeutic into the Impaction that's causing the Crop issues.
Report back and we can go from there with Impaction issues. I'm sure the experts here will chime in too. They are invaluable in helping work through chicken issues such as this...