I would get acidified copper sulfate fro Murray McMurray Hatchery or from Jedds.com. It is very accurately mixed and dosage is simple—1/4 tsp per gallon of water. Use it for 3 days a month as a preventative or for 5-7 days for treatment of canker or sour crop. If your bird has canker of the beak...
She may have suffered some internal injuries, but hard to know without a vet. Do you feel any air pockets under her skin around her chest, side or neck? I would continue to offer food and water, and make sure that she is in a quiet environment.
Ivermectin is not approved for poultry, and if you use it there is no official withdrawal time. Ivermectin was found in the eggs for up to several months according to this study:
https://pubmed.ncbi.nlm.nih.gov/39981309/
Are you using the Zimectrin for tapeworms, or have you confirmed worms. I...
Since her tail position is down and abnormal, I would give her 300 mg of human calcium citrate with vitamin d now in case she is having trouble passing an egg. Offer some fluids orally as well...
Very sorry for your loss. It would be worth getting the state vet lab to do testing and a necropsy. Keep the body cold/refrigerated. It sounds like she could have had colibacillosis (E.coli infection or other bacteria, such as mycoplasma G in her abdomen) causing egg yolk...
Valbazen, which is available now as albendazole 1/2 ml given orally once and repeated in 10 days is what I prefer. SafeGuard Liquid Goat Wormer or the Equine paste can be used 1.25 ml orally for 5 consecutive days and may be more easily found. Here is where to find albendazole...
Sorry about your hen. Molt can be hard on them, and they usually stop laying during the molt. It can be a time when an illness will become apparent. How does her crop feel first thing in the morning before she has eaten or drunk anything? Can you mix a small amount of chicken feed with water...
Since ivermectin has lost some effectiveness over the years in chickens, I would recommend albendazole cattle and sheep wormer 0.08 ml per pound of weight given orally and then repeated in 10 days. That is about 1/2 ml for a 4-6 pound chicken. Here is where to buy a smaller amount...
How old is she? Does she lay eggs? I would look her over for any mites or lice on her skin. Check her vent to see if it is dirty or there are any maggots. Can you try to get her drinking some fluids and electrolytes by dipping her beak to get her started? Scrambled egg bits and wet chicken feed...
Here is another link with legbone deformities:
https://www.researchgate.net/figure/Classification-of-leg-deformity-A-B-Normal-stance-with-mild-flexion-of-the-hock-C_fig1_332949715
I do think that it looks to be varus leg bone deformity. There is no treatment for it, and he may get around fine for most of his life, or he could eventually rupture his hock tendon. If varus occurs in both legs, they will have bowlegged appearance. The opposite deformity is valgus which gives...
I would continue to bring her outside and walk around with her, maybe while feeding some bits of egg or tuna as treats while walking around. Are her legs moving okay? I would leave the wrap off of her wing to get used to. Some supervised visits with her flock might help to get her back into the...
Good advice from alinas2010. Does the lump fell firm or slightly squishy? Can you see an opening to her ear where the dark feathers are above the lump? This can be a common place for abscesses, peck wounds or stings, and skin cancers. Squamous cell cancer is common there, and may have a crater...
If she passes any droppings that you can catch with a picture, you may post those. I have had a few hens like this, and when they died, I did a necropsy on each one which helped me know what was wrong. We appreciate any pictures of chicken necropsies here, and may be able to help with opinions...