Tylosin is the antibiotic we usually use for CRDs. (Chronic Respiratory Disorders) But you will need to ask a vet for a prescription.
CRDs are caused by a virus and once a flock is exposed to it, it becomes chronic, activated by stress. Usually, these symptoms resolve on their own, much like the rhino virus in us humans. It's when bacteria climbs aboard that serious illness can cause serious complications. So this is when we use an antibiotic.
Much of the time, when you are seeing your chickens sneeze, it's because of dusty feed being inhaled. If your chickens are having weepy eyes and nares and are listless, then you should ask a vet for the tylosin prescription. Often this med is added to the drinking water to treat multiple chickens.
