Starter feed wasn't included in the previous statement being the reason I said nutrient deficit so confidently.. which is still possible if the treats were in excess. Scratch and cracked corn are consdered treats, good for enrichment and high energy but lousy nutrient values. Adding the supplement is a good place to start, though I wouldn't rule out other possible causes just yet. Still cut out ALL treats until you see results. Only excepeption I might consider (short term).. a boiled and smashed or scrambled egg or other high quality protein like ground beef, canned mackerel, etc.
If she passes.. refridgerating the body and sending in for necropsy to get a diagnosis.. and see if the rest of your flock has anything to worry about or not (virus, parasite, disease, etc) might be a good idea.. I looked, it's $115 for up to 3 birds in your state. That's not super affordable for me.. contact info for your state..
https://nmdeptag.nmsu.edu/labs/veterinary-diagnostic-services.html
Veterinary Diagnostic Services
700 Camino de Salud NE
Albuquerque, NM 87106 US
505-841-2576
fax: 505-841-2518
Was she not walking before she got to you or is it a new development?
How is she doing this morning?