Here are some examples of other laws in the US:

• Belmont, MA. You may keep chickens on residential lots with a special permit. Inspection required.
• Newton, MA. Hens allowed by special permit on lots under 5 acres. Over 5 acres agriculture is allowed without a permit.
• Brookline, MA. (Article 4, table item 57) Poultry is allowed, not more than 25 animals and 100 away from any residence not on the property. Additional regulations may be applied by the board of health.
• Winchester, MA.  Keeping of animals such as horses, sheep, goats, pigs, etc. requires a permit.
  
• Lexington, MA. Up to 6 chickens allowed regardless of lot size.  Any livestock allowed on lots exceeding 5 acres.
• Cambridge, MA. Nowhere are chickens mentioned in the city codes, however commercial agricultural uses of residential properties are not allowed.
• Concord, MA. Allows for any livestock on all lots exceeding 5 acres. Has special zoning for agriculture.
• Medford, MA. Does not allow any agricultural uses of residential properties, although it appears if you call them “pets”, they are exempt from the restrictions.
• Watertown, MA. Allows for commercial agricultural uses on residential property only if it is 5 acres or larger, but non-commercial usage limits are not specified.
• Somerville, MA. Does not mention livestock or poultry at all, with the exception of being able to sell agricultural products on certain zone types, so presumably unregulated. Interestingly enough, the city website has a page on coyotes, and how to protect livestock from predation.
• Wenham, MA. Poultry allowed, but the town may restrict your operation if it causes a public nuisance (noise) or public health issues (disease).
• Westwood, MA.  Poultry allowed by permit.  $10 annual fee.  15 ft. property setback.
  
• Northampton MA. A maximum of three hens allowed; no roosters.
• South Portland, ME. (Ord. Sec.2 7-8.5) - up to 6 hens allowed, some restrictions. No roosters. Permit required - $25 application fee, $25 for coop inspection. (Portland Press Herald, Sept 7, 2007)
• Portland, ME. Allowed as of 2/2009 - hens only, no roosters. Permit required, $25. Must be at least 20 feet away from neighboring houses and 5ft from property lines. (From the Portland Press Herald 2/19/2009)
• Cape Elizabeth, ME. Pet chickens allowed! (Not for profit.)
• Biddeford, ME. (Part II Ch 10 Art 1) Chickens allowed in the city, no restrictions.
• Boston, MA. (Ch. 16, Sec 16.18A) Chickens allowed by permit, fee $20. Certain limits in residential areas, but these are not listed in the city ordinance.
• Concord, NH. (Title 1, Ch 13, Art 13-1) Unspecified number allowed. Cannot be a public nuisance or health hazard.
• New Haven, CT. Unspecified number allowed. Cannot be a public nuisance or roam at large.
• New York City, NY. Poultry allowed. You have to have a permit for your chickens. Must be kept clean. No roosters.  No limits on numbers, over 30 community gardens keep hens for eggs.
• Chicago, IL. Can keep as many chickens as you like but only if they will be your pets. You are not allowed to keep them for slaughter. You must also keep them penned.
• Burlington, VT. Up to 3 chickens per household.
• Portland, Oregon. You are allowed three hens without a permit. Roosters are not allowed. You need to apply for a permit to keep chickens. Permit for more costs $31. Any coop must be kept more than 25ft. from residences.
• Syracuse, NY. Chickens are sometimes allowed here. It depends on your zoning. No roosters.
• Mobile, AL. You can keep as many hens as you like here but no breeding allowed, and no roosters.
• Little Rock, AR. Up to four chickens allowed.
• Miami, FL. May have up to 15 hens, no roosters. Must be contained at least 100 feet from neighboring structures.
• Minneapolis, MN. Unlimited. Applicant needs consent from 80 percent of neighbors within 100 feet of real estate. Chickens must be penned.
• San Antonio, TX. Up to 5 chickens, any gender, per household. Must keep in a coop, 20 feet from any other dwelling.
• Rochester, NY. Requires a $25 license for keeping pet chickens; in the city limits, no roosters and no commercial breeding allowed. Coops must be kept 25 feet away from houses. Coops must provide a minimum of four square feet of room per bird. Your coop set-up must be inspected before adding chickens, to make sure it provides enough space and healthy conditions for the birds. Licensing and inspection is done through the Rochester City Police Department (Sgt. DeAngelo). The online city code which outlines this can be found in Chapter 30, Section 19.
• Madison, WI. As of 2004, it is legal to have 4 hens (no roosters) in a coop, no closer than 25' from the nearest neighbors living quarters. Butchering within the city limits is still not allowed.
• San Francisco, CA. Allowed.
• Houston, TX. Allowed.
• Seattle, WA.  Allowed.
• Los Angeles, CA. Allowed.
• Pittsburgh, PA.  Up to 5 pets allowed, including hens.  Zoning variance may be required in some areas.