I try to conserve the feathers for specialty arrows. Fire arrows for first boss and then for the trolls early on when you don't have a great bow and your bow skill is low. The birds can be killed during the day as well, but you have to be quick with a bow shot, and during the day when it's raining they are easy to kill as they go to ground. I never make flint arrows, not worth wasting the feathers on them, I save them for other specialty arrows down the road.