The fifth level will take a couple of tries to get. You have to hit every single pig in one go. More detail with regards to this level can be found below the video.
As many times before, pay close attention to the location of my mouse when I release (and speed up) the bird. Replicating this can save you a lot of time. It may still take a couple of tries as the angle and speed has to be just right for every pig to pop as a result of a single hit.