Chicken coops are small buildings used to house chickens.

Chicken coops in the early 20th century

Ann Arbor home owners with land holdings in town kept chickens as part of a homestead that included vegetable gardens and fruit trees. The David Allmendinger residence at 719 West Washington Street in 1905 was 1 1/2 acres, a little Belle Isle.

Having a victory garden -- including chickens, if possible -- was considered quite patriotic during the Second World War.

News

(Dec 4. via Ed Vielmetti's blog) from UPI in their "quirks" section:

City Councilman Stephen Kunselman told his colleagues during the weekend there is support among residents who like the idea of having access to "farm fresh" eggs, which some foodies consider to be tastier and healthier than the store-bought variety.

Sources