That med is a three-in-one med. It will treat the coccidia, the inflammation that caused the bloody stools and bacteria that attacks when the intestines get inflamed. So, there's no need for the Corid, too. Save the Corid to follow up with a week after you give the last dose of the sulfa.
The chick with the closed eyes may be suffering from coccidiosis the worst. Without the sulfa to treat the cause of the early blood in the stools and the bacteria that is probably still making it sick, it could die. Corid alone does not treat these things. It only blocks thiamine that coccidia feed on.