The age at which a rooster develops spurs depends on the breed. Some roosters completely develop spurs by the time they are 3 months old, but others may take up to eight or nine months.
A spur is a bony growth that extends from a rooster's leg. Spurs grow and harden as the rooster matures. Adult roosters use their spurs to fight other roosters and protect themselves from predators.
Chicken owners trim or remove their rooster's spurs so that the rooster cannot cause injury. Domesticated roosters may use their spurs to injure pets, other birds or humans. Spurs are easiest to remove before the rooster is fully developed.