A privately owned broiler flock consisting of approximately 3,000 Cornish Cross Broilers in three different age groups (4, 6 and 8 weeks) was seen by the Cornell Animal Health and Diagnostic Laboratory Veterinary Support Services in September 2012 for increased mortality rates and increased respiratory noise. On initial visit to the property, approximately 75-80 percent of the birds were showing signs that included lethargy, decreased weight gain, infraorbital swelling, stertorous respiratory noise and effort and occasional coughing. Examination of individual birds revealed large amounts of caseous exudate that could be manually expressed from the infraorbital sinus. A field necropsy was consistent with Mycoplasma gallisepticum. Tissue samples and blood samples were submitted for culture and serology and were positive for Mycoplasma gallisepticum. The advised control plan was to slaughter the 6 and 8 week old birds and to treat the 4 week old birds by adding Tylosin to the drinking water. Additional management changes were also advised for future flocks. Bacterial, viral and parasitic diseases are commonly diagnosed in backyard poultry. With the increased popularity of backyard flocks and the penetration of their meat and eggs into the human food chain, control and elimination of these diseases are of chief importance. In order to reach a resolution of these issues, outreach education programs, veterinary care, and increased oversight will be required.