I did quite a bit of research about this for my City Council. All you have to do is google around a little and you'll find the official web sites of every state saying that avian flu is NOT a problem to be concerned about re: backyard flocks. Here are some examples, as well as an NPR story about this exact issue:
This is representative of most state's health pages, and clearly says not to get rid of your chickens, scroll down to near the bottom:
http://healthvermont.gov/prevent/flu/birdflu/birdflu.aspx
http://www.npr.org/templates/story/story.php?storyId=5386289
For one thing, the type of bird flu that passes to humans has NOT been found in North America. It is on the other side of the world. For another thing, it is spread by poor sanitation, ie contact with poop/blood of infected birds. So, poorly-maintained large "factory" flocks are more likely to spread it than carefully-kept pet chickens. Also, theoretically your pet cat is more likely to be infected (from eating an infected migratory bird) than your penned chickens. Most importantly, avian flu (of any type, even the kind that doesn't pass to humans) is most likely to be contracted from infected migratory birds. So, free-ranging farm flocks that intermingle, say, drinking from the same pond as Canada Geese, are possibly at risk, SHOULD the virus ever reach this continent..... but confined backyard flocks are NOT.
I have a letter from our Maine State Veterinarian stating that proper sanitation and husbandry can lessen or eliminate any risk.
Obviously, knowing the facts and staying abreast of latest developments is important if you raise chickens. Clearly if there was an outbreak here we would have to get rid of backyard flocks. But for now, people should stop believing the media frenzy. They always use scare tactics.... turn off Fox news and find some real facts.... Look to experts in this issue, not people who don't really know (I would tend to believe the CDC, livestock scientists, etc rather than pharmacists).....Avian flu is not a cause for alarm in the United States right now.
Just my 2 cents....
Stacey