Can you really kill two birds with one stone?

I've spent the entire day launching projectiles such as stones, bricks, gravel and chairs at the Swans who frequent the lake, which runs through the Beauville manor, in order to prove it can be done. But so far, I've only managed to kill them as individuals. Should I continue this experiment in the name of science, or stop before the Queen hears about her Swan loss? A knighthood is at stake after all !