I understand that, for many people, their fears are based on a lack of familiarity with the animals in question. They have concerns about noise, odor, waste, disease, and/or rodents attracted to the chicken food. Of course, dogs also have the potential to create problems because of noise, odor, waste, disease, and/or rodents attracted to the food, but because people are familiar with dogs, these problems are accepted as a matter of course.
This dichotomy is explored wonderfully by Tim Krohn in an article he wrote on the subject for The Free Press. (Click here for the full article -- it's definitely worth a read.) He deconstructs the argument that "farm animals belong on a farm," by pointing out that domesticated dogs and cats were also initially intended to be farm animals, too.
You may notice that the arguments around allowing FPAs in cities often end up comparing chickens or dwarf goats to dogs (with unflattering results). After all, dogs are known to bite and behave aggressively toward people, whereas "attack" chickens or goats aren't an issue. Dogs carry far more diseases that are transferable to humans than FPAs. The manure from dogs (and cats) is toxic to humans and cannot be used as fertilizer, but FPA manure is great for the garden. Also, dogs tend to make noise when they're scared or threatened, whereas FPAs (because they're prey animals) respond to threats by becoming very still and quiet. And yet, cities happily allow dogs with no space restrictions and a minimum licensing requirement, but FPAs are typically banned outright or require expensive/extensive permitting.
[As a side note... because I bring up the above discrepancies in FPA debates, I am sometimes accused of being "anti-dog." In fact, I own a dog named Lucy, and she is in the running for the most adored dog of all time. So, no -- I don't hate dogs.]
But, back to the fervor that is often inspired by the idea of hens in the city. It is fairly easy to address concerns about noise, odor, waste, disease, and rodents. These potential problems are far less treacherous than many people assume that they might be, and they can typically be addressed using a city's existing animal ordinance (i.e. just apply the noise rules for dogs to chickens). However, that is rarely the end of the debate. Once any logical concerns are addressed, anti-chicken people often retreat to the stance that they just "don't want it" (as did the mayor of Longmont, in this article).
If the birds don't actually cause any problems, then why don't people want chickens next door? Every person has their own reasons, but there are a couple of things that I've seen stand out during the various discussions I've had. Sometimes it's a class thing -- farms (and everything associated with them) are seen as "dirty," whereas cities are modern and "clean." Of course, this is completely illogical, but that doesn't matter. It's the poor people, you see, who have to get their hands dirty with farmwork. Rich people can afford to go into the Safeway and buy their eggs in pretty white styrofoam cartons. This explains why often the fiercest anti-urban-chicken people are ones who grew up on farms, or are only one generation removed. They worked hard to get away from the farm and "move up" to the city, and the last thing they want is for the distinction between farm and city to get even a little bit blurry.
There's another reason why some people oppose FPAs in cities, and it's pretty controversial. Frankly, in some cases (not all, of course) there's racism at the root of it. There's worry that "those people" are infiltrating America, and bringing their filthy animal-keeping ways with them. (Of course, our "American" way of raising chickens in huge concentrated animal feed operations is plenty filthy, with the diseases to go along with it.) Some people think that if we allow the keeping of 6 hens in a city backyard, before you know it chickens will be roaming the streets and Denver will resemble Tijuana. If a newspaper runs an article on urban chickens, the comments section will soon become filled with references to "Mexico" and "third-world country."
So, all of the people who are advocating for FPAs in their cities have a lot to contend with, as do those who are quietly raising FPAs in their backyards. This brings me to a very sad story. I have a friend who has been lovingly keeping a small flock of chickens in a suburb of Wheat Ridge, just a few minutes from me. Her animals have not caused any problems, and her next-door neighbor didn't even realize that she still had her birds. However, two nights ago, someone sprinkled a fast-acting poison throughout her coop and run, including the birds' feeder and waterer.
Her birds all died, quickly. In addition to losing her chickens, my friend's wonderful organic yard is now a toxic waste dump. The police are pursuing the case.
I realize that 99.999999999% of the people who oppose urban FPAs would never dream of doing something as despicable as this. However, the fear-mongering and fervent anti-chicken rhetoric can have consequences.
The hens, on a happier day... what a tragic loss.