We live in a residential neighborhood, but it's pretty urban. It's very densely populated and though the houses have yards, most are tiny -- it's extremely common here to use the plots of grass between the sidewalk and the street for gardening. I was initially just surprised that people can tend front-yard gardens without getting all their produce stolen, but hey, I'm coming from a neighborhood where $3 basil plants repeatedly got dug up out of my yard. I was even more surprised that a lot of our neighbors also keep chickens. (The chicken in the photo is in an enclosure directly across the street from Oscar's middle school on the strip of land between the street and sidewalk.) In the summer the chickens from a nearby house frequently strutted down the sidewalk; a crudely printed sign on their fence noted that "It's okay if the chickens are out." (I notice that those chickens are now securely fenced in their yard, though, so maybe in the end it wasn't okay.)
Some quick research reveals that Seattle allows up to eight domestic fowl on any lot, but no roosters. You shouldn't keep just one chicken because they like to live in groups. Structures housing chickens have to be at least 10 feet away from the house.
Legality aside, it seems like a lot of effort to get eggs, and it must cost more to feed and house the chickens than eggs cost. I assume you have to heat the coop somehow; the temperature has been dropping to freezing levels at night. Also, the egg production rate lessens after a chicken's first couple of years, and some chickens lay eggs only in the spring. Do chickens make good pets? Personally, I find them intimidating -- ever since I learned that they're dinosaurs' closest living relatives I expect them to attack me like a velociraptor from Jurassic Park.
Still, the idea of a mini urban farm is sort of appealing to me, and I've heard that fresh eggs taste a million times better than store-bought ones. I am trying hard to be more of a locavore too. And we actually do have a chicken coop at the side of our house, though it's not 10 feet away. Is urban farming in my future?