If you have a hammer, I can offer you a better way....
Toast the bread, in the oven if possible (you can do more at a time, that way). When it's toasted and cool, put the bread into a bag (paper is more earth friendly, but plastic will do if that's all you have), and then get your frustration out on the bread.
A rolling pin will work just as well. For that matter, you could even walk all over it. My point is, once the bread is toasted and harder, you can use anything solid to make it into crumbs.
How can we sleep while our beds are burning???