This document summarizes chronic respiratory disease (CRD), also known as avian respiratory mycoplasmosis, in poultry. It is caused by the bacteria Mycoplasma gallisepticum. CRD commonly affects young broiler chickens and turkeys aged 4 to 10 weeks under poor management conditions. Symptoms include sneezing, coughing, and respiratory distress. Diagnosis can be confirmed via postmortem examination showing airsac lesions and a rapid plate agglutination test on blood. Prevention involves killing M. gallisepticum in hatching eggs by heating them for 2-3 hours then dipping in antibiotic solutions of tylosin, erythromycin, or gentamycin to expand and