Can she stand?
You mention she seems to have trouble moving the neck, do you see any bruising or injury along her neck or on her body along the back or under the wings?
You could deworm her with the Safeguard dose is 0.23ml per pound of weight given orally once a day for 5 days.
Treating for crop issues - this is the methods I use...
https://www.backyardchickens.com/ar...w-to-know-which-one-youre-dealing-with.73607/
The neck is puzzling. I think I would offer her Vitamin E (400IU) and 1/4 tablet B-Complex daily as well. If you get the Corid and decide to treat for Coccidiosis, then eliminate the B-Complex until you finish the course of treatment.
She is able to stand, and walk around - albeit she doesn't walk around much.
I was able to drop off poop samples for a fecal test, I collected hers and rest of the flock. So I will hold off on de-worming her.
Today is more-less the same, she hasn't been eating and drinking on her own, and we've been feeding her the Harrison's Recovery formula. I have not noticed any bruises, I've examined her body with my fingers and haven't seen her react with any pain.
In terms of behavior, she seems attentive, but lethargic, standing in one spot not moving much. I've taken outside to walk around a bit, she'd catch up with the flock but slowly. Inside while I'm with her, she instinctively crawls into my lap and stands on it.
I do have
Nutri-Drench on hand, I've mixed a small squirt w/ less than 8oz of water and been feeding it to her via spoon, as well as Rooster Booster electrolytes.
Her crop this morning was empty and malleable (even squishy, maybe?). She didn't poop too much overnight, mostly white droppings. She did poop a bit before I put her to bed, mostly liquid.
I went to the poultry supply store (where I've purchased my flock) and mentioned her symptoms to the owner. He thinks she's eaten something wrong and said to wait for it to pass.
There
is one thing that occurred a few days ago, a family member has a compost pile going in the backyard, that is fenced off from the flock. This past weekend the family member was turning over the pile and the smell was really pungent. I'm thinking Wheezy inhaled it and is that something that can affect chickens?
I have set up an appointment with the Avian vet after I had dropped off the droppings, but I am hoping her conditions improve where I don't have to go.