I hope you don't take this the wrong way but... Peking duck is a cooked duck dish. Pekin duck is a breed of duck. That 'g' makes a big difference.Wow!I've never seen a duck egg that small. Granted I'm still kinda new to ducks and my Peking that just started laying this August often lays double yolk which is ridiculous (3.5 inches long) but that's a teeny egg.
But like others said if it's fertile it could hatch and be fine. Your birds your choice. I would be in the "let's not hatch that one" camp.