I have 19 ten-week-old chicks who first began showing signs of coccidiosis two days ago, with two chicks seeming unwell, standing with eyes closed, not as active. I was also seeing lots of yellowish runny poops from random chicks and perhaps a hint of blood in a couple on close inspection. I began Corid powder 1.5 tsp per gallon that afternoon (Friday). They looked the same all day yesterday, but I noticed one of the two sicker chicks had a large, watery feeling crop but was eating and drinking. The other sick acting chick was more lethargic than before. I mixed up a concentrated dose for both yesterday evening and administered that. This morning, they still dont look any better, and I have another chick seeming to slow down. So today, I added Corid water to feed as well to make a mash. I know it can take a couple of days for them to start showing improvement on Corid, but how long should I give them before deciding it's not doing anything and start treating with an antibiotic instead for some other form of enteritis or something? Oh, and it has been rainy, warm, etc. here lately in Missouri, prime coccidia weather.