It doesn't matter whether it has veins or not. It could have died at any point, and if you can still see a lot of veins, it probably died earlier on, because a dark mass would be taking up most all of the shell. The veins will grow, and if the duck died, the veins stopped growing and are just there. I am guessing it died, but if you posted a pic, I could tell you. You can only tell if it's dead or not if you know what you are looking for in the egg.