The noun fowl usually means domesticated birds kept for eating or producing eggs. If your friend brings you eggs from the chickens she keeps in her back yard, you can say that she has pet fowl.
Fowl comes from the Old English fugel, "bird," meant simply that — "bird." Today, fowl usually refers specifically to chickens or other kinds of domesticated birds that lay eggs or are raised to be eaten. Occasionally, fowl is used interchangeably with poultry, to mean the flesh of that same kind of bird when it's eaten; you could describe your family as being fond of pork, beef, and fowl.