I think you can get Vecoxan at stores.. not sure, ... Baycox, which I believe is stronger is VET only.
You need to dose today, do not delay.
You will need to do everybody... goats, sheep, cattle.. on your land. It is a weight related drug but not precise to the last ounce.!!!
This is animal specific.
Usually the first signs of cocci is a dead animal... you may be lucky. But I do not like the sound of the blood. It could also be caused by a huge worm load having damaged the gut despite regular worming.
My money is on cocci.