Hello and welcome. First please segregate the sick birds from the flock if you haven't already. You can put the sick ones in together in a pen but separate from the healthy ones. Disinfect the waters and feeders of the healthy flock, and if you can get Oxine, that is the best disinfectant, but at least disinfect as much as you can with bleach. They need an antibiotic, Baytril would be best. You can get it on line, or through a vet, if you have a vet that will treat chickens, take just one bird to the vet if you can, and get a diagnosis. I seriously doubt it is cocci with extreme symptoms like that. How old are they and where did you get them, and how long have you had them? Have you introduced any new birds into the flock recently.? If you have new birds, contact the previous owner for information about what could be wrong. If one of your birds dies, you can get a necropsy done, some states will do one for free or at a low cost, but it has to be done within twenty four hours of death and preferably the dead bird should be refrigerated. Do they have watery or swollen eyes, do they have an unusual odor from the breath? Are they eating ok? Have they ever been dewormed? Make sure they are eating, you can give them bread moistened with buttermilk, or scrambled eggs, banana, chopped grapes, applesauce mixed wtih crumbles, oatmeal, whatever they like. If nothing else, you can get Oxytet at the feed store, or even Duramycin, and mix two teaspoons in a gallon of water, and give them that. Injectable Tylan can be injected or given orally, ask the store for guidance with this, or there is information if you search on here about the proper dose for Tylan. Veterinary care is always best, if you can. This is an emergency, when birds are showing extreme sick symptoms like you describe, they are already very ill. They hide symptoms as long as they can. Please keep us posted, and continue to describe symptoms the best you can.
