Okay newbie here(obviously), I saved a nest of Mallard eggs from being plowed under in a field. That was Monday. On Monday I candled before I put them in the bator and saw little embryos maybe the size of a dime or a bit bigger. One egg was cracked and weeping so I tried to open it to see what was inside. Anyways I got grossed out and only glanced at this little maybe marble sized thing, it did have feather already( I tell you all the background in case some one can tell about how far along they were.) Well today I candled these eggs to see what was happening and maybe 1/2 to 3/4 of the egg was dark, almost black. Did these duckies have a tremendous growth spurt or did the eggs go bad? I THINK I can still see movement, but the difference from Monday to today is astounding so I feel like something must be wrong. Please advise.