The proportions are two teaspoons per gallon of water given five days, a week off, then five more days to catch any oocytes that have developed into coccidia. Your dosage for the drench is correct. But some chickens go on to develop a bacteria infection on top of the coccidiosis. This bacteria eat the intestinal lining along with the coccidia. It can be fatal. Sulfa can often turn this around if caught in time.