An 6.4 oz package of Terra-Vet 10 contains 38 teaspoons. If you want to treat chickens with approximately 600 mg, the entire package will do about 19 gallons. Dividing it further is as follows:
2 tspn to a Gallon
1 tspn to a 1/2 Gallon
1/2 tspn to a Quart
1/4 tspn to a Pint
1/8 tspn to a Cup...