if i candle my eggs today(7th day) what will i be looking for?
if your eggs are brown, you may want to wait till day ten. The darker the egg shell the harder it is to see the veins and early stuff. But when you candle if you can't see any lines for veins or a mass kind of wrapped around the middle like a ring, don't toss the egg right away, instead mark it and wait 3 days to see if maybe it is not a dud.
Another thing to consider is keeping the incubator warm. Many people remove a few eggs at a time, close the incubator, candle, put those eggs back and wait for several hours before doing the next batch.