Blood feathers

Poor Bezukhov has some blood feathers.

I understand that blood feathers & pin feathers are much the same thing in that blood feathers are usually pinnies.  Pin feathers do not always have a visible blood supply though, as it can have receded but the feather still be in a waxy coating.

Blood feathers sounds more appropriate in this instance as it is possible to see the blood supply.  It looks very uncomfortable.