A hobby farm is only somewhat like a real farm, given that it is much smaller, and rarely is the primary source of income for the 'farmer'...
Generally, a hobby-farm is a small piece of land with a house, an assortment of animals, and various assorted junk, which someone who either can work from the propery itself, or who commutes to work from the farm would buy as a place to relax and tinker to their heart's content on weekends, and possibly actually grow things