I'm currently incubating duck eggs, (8) and I need some help. we're on day 18 now, and we candled them. 6 look really good, and the ducklings are moving around. 1 of the "bad" ones is really light (lots of open space inside) and there appears to be a blood stain on the inside of the shell. no embryo in sight. the other "bad" one is SUPER dark inside. there are small veins on the very bottom, but there's no movement. is it rotten? I need to remove it if it IS rotten so that it doesn't explode. TIME IS RUNNING OUT! PLS HELP!