Nothing wrong in shooting a duck (or anything else)to eat imo.It needs to be shot by someone who knows whats what though,so its a clean instant kill. A brain dead retard who shoots a crossbow bolt through its neck and then leaves it like that,should suffer the same experience.
And that is the crux of the matter ... as a kid I was taught that if I didn't shoot well enough to kill the target .. fowl or game ... it was down to me to track the animal, find it and dispatch it humanely.
I spent many hours wandering woods to do so .. and if it taught me nowt else, it made sure I only shot when I was certain to hit .. risky "possibles" wasted too much time searching and not shooting.
It is the leaving of this bird in this condition that is appalling, as it is "possible" that it was actually shot to be eaten ... but somehow, given the choice of weapon, I doubt it.