Please help with Tylan 50

[Pillzzner]

I posted earlier about a sick chicken...yes shes still sick but hanging in there for now. Local feed store said to get Tylan 50 antibiotic and inject in breasts of chickens...not just the sick one but all. Well...gave all chickens 1cc injection Tylan...about 10 minutes later they all act drunk....could not fly to roost...not acting sick, just disoriented. Is this normal? I had to help my girls up to roost...my roo seemed normal like nothing happened. Also with the Tylan...I'm not even sure what I'm treating...guessing a precaution...do I only do 1 injection and thats it...or do I need to do this for a few days? very confused