oegblady....sorry to hear about your loss.
think positive about your hatch! Sometimes they are a little slow.
I had two separate batches of quail (i know, not ducks, but birds and hatching similarities) that I put in the bator 10 days apart....then I got em mixed up a bit. I had one batch in cartons, the other not, and the bator got bumped (i am VERY clumsy)...a couple fell out. I thought I had thr correct ones...NOPE!
I leave em till they smell anyhow...but six full days after the hatch, I had a couple extra quail running around my bator!!! They werent due for another 7 or so days! ...I cant imagine quail being seven days early since they only incubate for 15 ish!
Keep em till they stink...then you will KNOW without a doubt that you didn't toss em too early...one less reason to kick yourself!
Good luck!