What are feathers called that are still growing and receiving blood through the shaft?

Feathers that are still growing and receiving blood through the shaft are referred to as blood feathers. This term highlights an important aspect of their development and functions. When feathers are in the growth phase, they are wrapped in a sheath, and a blood vessel runs through the shaft, providing essential nutrients and oxygen to the feather. This is why they can appear darker or more vibrant compared to fully formed feathers. If damaged, blood feathers can bleed and may require special attention to avoid harming the bird.

Down feathers, on the other hand, are soft and fluffy, primarily serving to insulate the bird. Flight feathers are the long, stiff feathers critical for flight, while contour feathers cover the bird's body and help shape its appearance. Each of these types plays different roles, but only blood feathers are specifically characterized by their stage of growth and blood supply.