Talking about whether they sit for weeks in the wild, they dont , in the wild birds of prey moult in a different way when moulting out wing feathers they will moult out symetrically so the very end feather on one wing and the very end feather on the other wing and this helps keep their balance and enables them too keep hunting through the moult. in captivity generally birds of prey just moult out feathers at random and thats to do with the different weights that we keep our birds at, in the wild a bird will be going constantly from fat one day to hunting two days later to fat for a few days de