In your first post I see your guineas outnumber your chickens, I would get them out of there. Guineas are tough and smart, and will harass your chickens- bully them away from the food and water. I do not think the guineas specifically made your hens sick, but they are not helping with the stress level for the chickens.
Coccidia may be your problem, diagnosis is made on a fecal float at the vet's or guesswork based on probable exposure (dirt) and clinical signs (droopy bird, diarrhea often with blood). Get your sick birds out of the cold coop and into a warm and safe environment- you can better monitor food & pooping + making sure the bird(s) are actually getting the medication. A really sick hen will not drink the medicated water. How are you giving the meds? In the water or by syringe? If she is not eating/drinking- you need to help her, she will die from the dehydration and cold.
It might not be coccidia, you should also inspect them carefully for lice on the birds, and mites in the coop at night. Many other possibilities too. If another bird dies (or you cull due to severe illness) send it to your state lab for necropsy if you can- you will get your diagnosis for sure that way.
Coccidia may be your problem, diagnosis is made on a fecal float at the vet's or guesswork based on probable exposure (dirt) and clinical signs (droopy bird, diarrhea often with blood). Get your sick birds out of the cold coop and into a warm and safe environment- you can better monitor food & pooping + making sure the bird(s) are actually getting the medication. A really sick hen will not drink the medicated water. How are you giving the meds? In the water or by syringe? If she is not eating/drinking- you need to help her, she will die from the dehydration and cold.
It might not be coccidia, you should also inspect them carefully for lice on the birds, and mites in the coop at night. Many other possibilities too. If another bird dies (or you cull due to severe illness) send it to your state lab for necropsy if you can- you will get your diagnosis for sure that way.