It has to be put in the water 2 tsp of the liquid or 1.5 tsp of the powder per gallon of water They take a normal amount of water, and they get the correct dosage. It is not to be given orally, except as a drench once a day to give a starting boost. That dosage is 0.1 ml of undiluted Corid per pound once a day.
The boost is just needed if the chicken is especially sick or weak. Otherwise the treated water is enough. Is your sick chicken drinking normally? The dosage of the treated water is standard for an outbreak. You can make smaller amounts if treating only 1 or 2 chickens. There is also a smaller preventative dosage.