There are twelve (12) feathers in an eagle tail, five (5) from the right side of the tail, five (5) from the left, and two (2) center feathers.

Taking the tail apart, we will lay out half of the tail from the left side of the bird.

Center or Chief's Feather

NOTE: Going from center to outer edge of the tail, the feathers become more curved and one side becomes wider than the other.
Knife Feather or Roach Feather