I recently bought a few 1 year old hens that all turned out to have a respiratory disease. The vet gave me some baytril and I have been injecting it every day and tomorrow is the last day of treatment. How long should I wait before introducing them back to the rest of the flock? How should I sterilizing their quarantine area? Also. some people have told me that I can't sell chickens/hatching eggs from my flock anymore because "they will always be carriers" is this true? thankyou all.