Although the disease tends to run about 2 weeks and birds tend to recover from it, they can also still harbor the disease for a long time, or, in some cases, permanently. This means chickens that have had Avian Coryza can still infect other members and new members of the flock even if they are no longer exhibiting symptoms. Aerosols, contaminated feed or water, and even equipment can also transport and spread infective bacteria.
The disease can be treated with several antibiotics, which can be administered through feed and water. Tetracyclines are the most common antibiotics used for treatment. If the disease is not widespread, you may be able to use depopulation to lower the risk of spreading the disease.
If depopulation is not an option, quarantine the affected flock, whether they are recovered or are actively sick, and avoid bringing any new birds or replacement birds on the premises. Once the affected flock is removed, thoroughly clean and disinfect everything and implement a 3-week waiting period, at least, before repopulating your flock.
If you are located in a region where Avian Coryza has become widespread, there are vaccines available and you will want to enlist the help of a professional to get the right one. It must match serotype A and should be given several weeks before the birds are moved into a high-risk location and well before the onset of lay.