According to the CDC (Center for Disease Control), Salmonella is one of the most frequently reported food borne illnesses in the US. Salmonella is a bacterial disease that lives in the intestinal tracts of animals (including humans & birds).
Approximately 380 people die annually in the United States from the disease which can cause vomiting, diarrhea, fever and severe abdominal cramps. Is Salmonella something you should be concerned about if you keep backyard poultry? Yes. Is it a reason not to keep them? Definitely not! As long as you are keeping a clean coop and use common sense, I think keeping backyard hens actually can lower your risk of Salmonella poisoning.