Sick chicken

[Halehson]

Sick chicken 2 years old. Empty crop, purple comb, laying down a lot, not eating or drinking. Poop is more yellow than green now. Have been giving her electrolytes, poultry cell, and b-12 by syringe and she is alone inside where it’s warm 3 days now. She sounds kind of wheezy when she talks so I put some vet rx on her beak. No other chickens are sick. I have Corrid and ivermectin (the horse one) on hand. Not sure what to do. Wont eat scrambled egg.