please tell me, what is this coccidosis and how is it caused? (Sorry, I'm new to the diseases with chickens)
It will make your chickens stumble around, walk funny, ball themself up while standing, poop blood, become lethargic, stop eating, ect.. Kills them in a week if they get it and it goes undetected.
Its a type of microscopic parasite. I forget how many different types their are that effect chickens. Its in the soil and if the chickens food hits the ground and they eat where the coccidiosis is it can be transferred to them. If a chicken has it its in their poop, and if other chickens eat off the ground where the poop is, it can transfer to them quickly. I lost a few dozen chickens over a few years before I understood how to properly take care of it.
You might have one strain of coccidiosis in your yard then your neighbor across the road could have a different one. Yall might trade chickens then your chickens catch his strain because they didnt have an immunity to it.
I recommend to alway treat your chickens when you buy new ones and ask if they have been treated for coccidiosis, worms, and had any vaccines before purchasing new chickens.
Never use "Sulmet" for coccidiosis, it only treats a couple strains and it is toxic. Kindof like chemo with cancer patient, it might make them better but if they are too weak and then are treated it can make them worse and even speed up their death.
I recommend "Corid" you can research proper dosing on here, its not harmful to the chickens and you can routinely treat your chickens year round to avoid any outbreaks, especially if you begin bringing in new chickens from other flocks. Worth a google search and reading up on coccidiosis.
Coccidiosis and mites have been the biggest hassles while I raised chickens. Also routinely treat for worms, avoid a lot of hassle in the long run.