Layman's version:
Maximum 10 chickens kept 20 feet from any property line and/or building.
 The Urban Chicken ordinance on the books:
Link to municipal code online: Title 7: Animals
Text of municipal code:
7.36.010 Domestic fowl—Restrictions.
Except upon premises zoned for agricultural purposes pursuant to the Zoning Ordinance, no person shall keep any goose or turkey, or more than 10, whether singly or in combination, of the following: ducks, chickens, or pigeons. (Ord. 1293 § 1 (part), 1975: prior code § 3.90.)
7.36.020 Domestic fowl—Enclosure.
Any domestic fowl permitted to be kept by Section 7.36.010 shall be kept in a sanitary enclosure, which enclosure shall not be located within 20 feet of any building or property line. (Ord. 1293 § 1 (part), 1975: prior code § 3.91.)