Anyone can try urban farming! Even if all you have is a single pot of plants, as long as you are growing something and eating it, that's farming. And that one single act has the power to change the world.
My friend Willa from Sonnewald Natural Foods says that even if you don't have the room and sun for a pot, you can grow your own sprouts in a jar.
Raising things yourself doesn't only have to be about producing food. You can raise other useful raw materials such as fiber or wood.
Some people raise small livestock animals like chickens, ducks, or miniature goats in an urban setting. We have tried raising an angora rabbit for fiber, in addition to the silkworms I mentioned above. Otherwise we stick to honeybees.
Microlivestock is a term often used for insect livestock because they are so small.
I had two laying hens to produce eggs when I lived with my parents, so I do have some experience with small flock chickens. We attended council meetings and wrote letters to help change the laws to allow urban chickens in our area, and we won!
But the rules are still not well-written, so there are extra work, hassles, and fees involved. You are expected to buy a permit and have your coop inspected and so many feet from property lines, not the kind of movable free-range coop arrangement I like. And I currently have taken eggs out of my diet anyway. We could raise chickens for meat, but it's just not worth it. We have plenty of other projects to keep us busy!