A young hen is usually referred to as a "chick." In most cases, the title "hen" refers to an adult female bird; in domestic terms, a hen is an adult female chicken that has reached maturity and can lay eggs. Birds normally incubate their eggs for a period of between 2 weeks and 30 days before the eggs hatch into chicks.
Most adult male birds are referred to as "cocks." The male of a chicken may sometimes be referred to as a "rooster," while male ducks are called "drakes." In most bird species, the males are larger in size when compared to females.