The severe outbreak dosage (which is what I would recommend) is 1.5 tsp per gallon. If chickens drink normally they will get the correct dosage they need. If they don't drink, then use a dropper to feed them.I have the 20% corid. I think i will add it to the water tomorrow just to be on safe side. 1 tsp is what i add to a gallon correct? Will this hurt the 7 week old pullets?