Cocci can hit hard and quick as previously stated. Especially when you live in an area that is dealing with horrendous humidity for weeks. I always use Corid and PLEASE make sure to mix powered milk in their feed...50/50 because Corid is hard on their stomachs....really many meds are. So this will not complicate the problem during treatment.
I will tell you some advice given to me that has really helped in preventing cocci. The day your chicks are hatched starting taking grass and cut it up to let them eat it...do this every day. This exposes them to what will help build up their immunity system. I usually take a stick from outside when they are a week old to sit on and play with. If you think about the old broody hen with her chicks...she takes them out usually on the second day to scratch around in the dirt and grass!! Hope things get better!
I will tell you some advice given to me that has really helped in preventing cocci. The day your chicks are hatched starting taking grass and cut it up to let them eat it...do this every day. This exposes them to what will help build up their immunity system. I usually take a stick from outside when they are a week old to sit on and play with. If you think about the old broody hen with her chicks...she takes them out usually on the second day to scratch around in the dirt and grass!! Hope things get better!