tetracycline dosage

Hello! I need to start a course of tetracycline for my chicken (5 and a half years old rooster) as he has breathing issue which is not going away. I have tetracycline hydrochloride water soluble vet. It says to give 5 mg per 4.5 litres of water at the back of the package to treat poultry...

I have 40 total chickens. Bought at a local feed store. I will put the day I bought them the breed and how old they were when I purchased. 3/16: 1 Buff Orpington- 1 week old 3 Blue laced red Wyandotte- days old. 3/22 1 dark brahma -days old. 3/29 1 black sex link 1-2 weeks 3/30 6 Ameraucana...