What is a feather bomb?

The words "feather bomb" are never used in the text. The only mention of feathers is as follows;

First Arrow Day—when he had used thread from his tattered old piece of windbreaker and some pitch from a stump to put slivers of feather on a dry willow shaft and make an arrow that would fly correctly. Not accurately—he never got really good with it—but fly correctly so that if a rabbit or a foolbird sat in one place long enough, close enough, and he had enough arrows, he could hit it.