Hi lady ... Long time.Wormed? No bugs? Is her crop filling and emptying daily? Will she eat a wet feed mash? If all this is good, my first tx is usually for coccidiosis for 5 days. My animal disease lab vet stated to me that cocci numbers increase in backyard situations and can actually give chickens a larger amount of cocci without making them sick just unthrifty because they get used to it. He recommended treating for cocci 2x a year. This statement is from the head vet of the Florida ànimal disease lab in Kissimmee Florida. They do all my necropsies and he's okay with phone calls.
After that if no improvement, I treat with an antibiotic. I feel that if the chicken may die, I can see a vet, do nothing, or give a general antibiotic that covers e. coli, clostridium, and staph. Aspergillosis is a common silent killer but there's hardly a treatment that works.
Many may not agree with my system, but based on knowledge attained and my necropsy results, this is what I do.
deb