The easiest way to tell if a chicken is a rooster is to see if it lays eggs or crows; if it crows, it is a rooster, and if it lays eggs, it is a hen. If the chicken is too young to lay eggs, additional clues, such as the color of its comb, can help determine the gender.
Young chickens may exhibit small differences depending on gender. For example, roosters have pointed neck and back feathers while hens usually have rounded feathers in these areas. If there are two or more roosters together, they may try to intimidate each other by puffing out their neck or hackle feathers; hens do not do this.
The feathers on the top of the chicken's head are called the comb feathers. Rooster combs are more pronounced than hen combs, and they turn red at a young age.
Roosters also tend to have thicker legs than hens. Near the base of a rooster's leg, he has a sharp spur. This spur is used for defense. Although this is a prominent characteristic of roosters, it can be mirrored on older hens. When found on mature hens, spurs tend to be shorter and less prominent than those found on roosters.