Los Altos, CA
 Layman's version:
1 hen per 1,000 square feet of lot space. No restrictions on coop location. No roosters.
 The Urban Chicken ordinance on the books:
Link to municipal code online: Chapter 5.10 Animal Control Regulations in R1/R3 Districts
Text of municipal code:
5.10.010 Permitted animals in R1 districts.
A. Animals may be kept in the R1 districts in accordance with the following regulations:
1. A maximum of three dogs shall be allowed, regardless of the site area.
2. A maximum of one cat shall be allowed for each three thousand three hundred (3,300) square feet of lot area.
3. A maximum of one small animal, including pigeons, ducks, geese, chickens, peafowl, rabbits, and other animals of a similar nature, shall be allowed for each one thousand (1,000) square feet of lot area.
4. A maximum of one medium-sized animal, including sheep, goats, and other animals of a similar nature, shall be allowed for each ten thousand (10,000) square feet of lot area; provided, however, no swine shall be allowed, regardless of site area.
5. A maximum of two large animals, including horses, cows, donkeys, and other animals of a similar nature, shall be allowed on a site not less than two acres in area; provided, however, one additional large animal may be kept for each additional acre of the site.
6. A maximum of one honey bee hive shall be allowed for each five thousand (5,000) square feet of lot area; provided, however, neighbors and passersby shall be protected from flyways, and a water supply adequate in quantity shall be provided and maintained on the site.
7. Exotic, wild, or nondomestic animals shall be allowed only after first obtaining a permit from the health officer; provided, however, the quantity of such animals shall be regulated in accordance with the provisions set forth in subsections (A)(3), (A)(4) and (A)(5) of this section.
B. The provisions of this section shall not be retroactive; however, any person keeping in excess of the quantity of animals permitted prior to February 28, 1978, shall not be allowed to replenish the number, except in compliance with the provisions set forth in this section. In the case of honey bee hives, however, any person keeping in excess of the quantity permitted shall be required to reduce the number to be in compliance with the provisions of this section no later than February 28, 1981, or, in the event of an annexation, within three years after the date of the annexation.
(Prior code § 10-2.6501))
5.10.070 Sanitary maintenance.
Any enclosure or premises where animals are kept shall be maintained in a sanitary condition as set forth in Chapter 5.04 of this title.
(Prior code § 10-2.6507)