When a chick first hatches its covered with a light grey down.  But by about three weeks of age a darker-grey down develops and the legs turns flesh colored to yellow.  By about the fourth year the young eagle begins to look like an adult.  For the first three weeks of their lives, the eaglets are watched over constantly by their parents.  A young eaglet can gain up to six ounces a day, the fastest growth rate of any bird in North America. 
Chicks are born with relatively large bills and legs.  Some body parts, such as the legs, are fully grown about half way through the nesting period, while the bill and flight feathers continue to grow after the eagle has left the nest.

  The young eaglets crawl about the neston their shanks, but by five weeks of age when they weigh more than four pounds, they are able to take a few steps.  By six to seven weeks of age their grey down is sprinkled with dark brown feathers, and their wing quils are begining to emerge.  Young eaglets will play tug-of-war with each other with sticks. By eight weeks of age the eaglets are strong enough to flap their wings, lift their feet off the nest platform, and rise up in the air.  When they are learning to fly they have difficulty landing.  Aggression between nestlings is common and occasionally resulted in the death of a young eaglet.  Young eagles weigh about a pound or more than their parentswhen they leave the nest but they lose this weight once they begin to hunt for food by themselves.