Feed costs money. Unless you live in an area where feed is very cheap, or grow your own feed, this isn't going to be economically viable. Having said that, some people enjoy keeping chickens as pets, and in that case economic viability takes a back seat. Plus there's a certain psychological satisfaction akin to tending to your own (also not economically viable) garden, which should not be underestimated. When I had a garden my every morning started with tending to it, and that was basically the most psychologically enjoyable thing I'd done in the last 30 years, especially when there's something to harvest. Plus, when AI neo-feudalism takes over, I won't starve. :-)