Your attempt to save a baby bird had two very strange decisions:
1. You left a rock on a baby bird
2. You tried to feed a dead bird some worms
Everyone deals with death differently, so passing judgment on your decision to sort of mutilate the corpse of a baby bird might not be the right thing to do. It feels like the right thing to do, but it probably is not. Or maybe it is. It is really hard to tell.