I'm on day 7 with two pekin duck eggs. I noticed veining on day 3 or 4. I watched a few videos and on day 7 you can see the embryo. When I candles my eggs today I saw more veining but half the egg is dark. It wasn't completely dark in the room though. I'm candling from the top (through the air sack) with the light shinning down. I'm going to look again with completely darkness later. Does that sound like my babies died since half the egg is dark? Am I candling correctly?