The domestication of plants and animals has led to important changes in the biology and the genetic diversity of domesticated species, and at the same time setting a new way of life for humans. In this process, several species of birds have been domesticated across all continents. This chapter reviews the current theories about the pathways leading towards domestication and presents the concept of domestication center. This chapter also reviews a number of bird species belonging to very different orders, i.e. Galliforms, Colombiforms and Ratites, the early phase of domestication, the dispersal of these species to different regions of the world, and the extent of genetic diversity currently existing.