Hi everyone. I candled my eggs today ( day 7 ). In some of them it was plain to see they were doing well, some were moving, good veins etc. But in more than a few all I could make out was a large "shadow". Is this good or bad. Three eggs looked blank or clear so I pulled them ouy and opened them. I was right--nothing was happening in there. Any one know what the shadow I am seeeing is? Thanks guys!