Why are you so certain its coccidiosis? It could probably be a number of things. Have you tried using the chicken symptom checker tool? http://www.poultrydvm.com/views/symptoms.php
I think it would be a good idea to bring her to see a vet who sees chickens....here is a directory - http://www.poultrydvm.com/poultry-vets.php. They arent as expensive as you would think.
That is ridiculously cold for any creature. You really need to provide them some warmth or bring them inside your house for the remainder of the winter. You're birds are going to either die from the stress and/or all loose their body parts to frostbite. Here is a good infographic with options...
It might be a good idea to take him to see a vet who sees chickens. Wry neck is a symptom of a disease, not an actual disease itself. It is not always a vitamin deficiency. Here is some good info on wry neck - http://www.poultrydvm.com/condition/wry-neck
I am not sure what your talking about since fleas mainly live on the bird. Perhaps your thinking of mites? Regardless, here is a good infographic which describes the difference - http://www.poultrydvm.com/featured-infographic/identifying-common-ectoparasites-of-backyard-poultry, and if it really...
Please throw it away. Poultry feed has a high risk of contamination with mycotoxins. If your birds aren't eating it, there is a reason. Here is a good infographic with info about this - http://www.poultrydvm.com/featured-infographic/mycotoxin-effects-on-poultry-infograph
Please bring the little bird to a vet who treats chickens. Dogs carry a bacteria in their mouth (well LOTS of bacteria actually), but one in particular which causes acute fowl cholera. So even if he survives the injury, he may die from sepsis if he is not given an antibiotic. Here is a directory...
I would predator proof your run to prevent all of the above from killing them one night. Here is a good infographic with tips on how to do this - http://www.poultrydvm.com/featured-infographic/tips-for-protecting-poultry-from-predators