There's a special kind of anxiety that comes with being a first-time duck mom. You have thirteen precious eggs. Your girl has settled on them for days. Then you realize some aren't viable, and suddenly every shadow on a shell feels like a verdict. The original poster brought us a story that any chicken keeper, or duck tender, knows in their bones. You want to trust the process, but you also want to peek. So you grab a phone flashlight, hold your breath, and try to read the future through an eggshell.
Here is the honest truth about that flashlight method. It is a rough tool, not a prophecy. A dark, solid mass with visible veins is a good sign. A clear, empty glow? Probably not your lucky duckling. But speed matters. Our OP snapped quick pictures to avoid disturbing the mother, which is the right instinct. A stressed duck might abandon the nest, and a cold egg is a lost egg. So the practical advice for anyone in this situation is simple: trust your eyes but trust the mother more. If she is still sitting, still rotating, still talking to them, give it time. A phone flashlight is not a crystal ball.
What we would tell a reader who asked us about this is that you are not alone in this fowl play. Every first-time hatch is a mix of hope and second-guessing. The push and pull between "Let me check again" and "Leave her alone" is the whole sport. The OP started with thirteen eggs. Some dropped off. That is normal, not a failure. Ducks are not perfect parents on day one, and neither are we. The real skill here is patience with a side of gentle observation. Do not candle every hour. Do not panic over one cloudy picture. If the mother is committed, she will do most of the hard work.
So here is the concrete point: pick a day, maybe day ten or fourteen, do one honest candling session, and mark your shells with a pencil. Then step back. Let her sit. Let the eggs do their quiet magic. You have done your part. Now the little webbed feet have to do theirs.