While the State Fair's ban on birds is unusual in recent history, it's not the first time steps have been taken to limit the animals on display. Previous incidents include:
1939: Certain exhibitors' birds were placed in quarantine by the fair's poultry department after showing signs of respiratory disease.
1943-45: There was a war-related suspension of exhibitions of livestock and poultry and of the horse show. The government took over the horse barn, the livestock pavilion (cattle barn), the swine-sheep barn and poultry barn, the hippodrome, the commissary and the arcade buildings.
1946: Before the entire fair was canceled because of a polio epidemic, on July 12 the poultry show was dropped at the request of the State Livestock Sanitary Board after Newcastle disease was discovered in the state.
1947: Newcastle disease and negative publicity limited the number of poultry exhibitors.
1952: All public exhibitions of swine were canceled because of an epidemic of vesicular exanthema. (Interesting aside: The swine barn was made the location for the atomic energy exhibit.)
1977: Pseudo rabies forced cancellation of the 4-H and Future Farmers of America (FFA) swine competition and reduced the number of swine entered in open classes from 1,657 in 1976 to 644.
2009-12: Swine-borne flu strains infected people around the state of Minnesota. Fair and state officials convened and concurred that the risk to the general population was low and agreed that the exhibition of swine at the State Fair should be allowed.
Source: Minnesota State Fair