Order of fowl-like birds which include seven families: Phasianidae, pheasants, partridges, and quails; Tetraonidae, grouse; Megapodiidae, mound-makers; Cracidae, curassows and guans; Numididae, guinea fowl; Opisthocomidae, the hoatzin; and Meleagrididae, turkeys. They are a widespread group, being found in almost every part of the world.