San Mateo County, CA Animal Ordinances: Chickens & Livestock (2026)

The County of San Mateo Poultry Ordinance provides guidelines for keeping domestic poultry (chickens and ducks) in residential communities in unincorporated areas, administered by the Planning and Building Department. Under the ordinance, a residentially zoned parcel must be at least 2,500 square feet to keep poultry. The number allowed scales with lot size: parcels greater than 2,500 square feet (up to 7,499) may keep no more than 6 chickens or ducks, and parcels of 7,500 square feet or larger may keep no more than 10. Roosters are prohibited because of noise. All poultry must be kept in the rear yard in a coop that is no larger than 100 square feet and no taller than 6 feet. The County's published material points to the zoning regulations (the County cited zoning code section 6401.1.1) for additional coop size and location detail. These poultry limits apply specifically to residentially zoned land in the unincorporated County; larger-scale or commercial agricultural operations on agriculturally zoned parcels are governed by separate zoning provisions. Because San Mateo County reorganized its Planning and Building regulations into a new Title 8 (Development Code) effective in late 2024, residents should confirm current section numbering with Planning and Building before building a coop.