Eggs that haven't made it?
The first one is dead (ring of death); the second one I would leave in the incubator and candle it again at 14 days. I had an egg on my last hatch appear to be non-developing every time I candled it, but it surprised me by hatching---zipping around it's shell cracking through the words "questionable" and "not developing day 14" I had written on that egg :)
As long as there are no cracks in the egg; no oozing or foul odor, you shouldn't have to worry about the egg exploding in the incubator. Hope you have a good hatch! :)