Thank you for all the responses!
I opened the three eggs that made it to hatch day but didn't hatch. One was not fully developed--it was the size of the yolk sac, and obviously not complete, though it was recognizeable (and stinky). The other two were apparently fully developed, one with the...
Oops--walking wolf, we were posting at the same time. Maybe for me my next hatch, I'll try simply not washing, even if they're filthy. I have to say, though, when my ducks occasionally go broody, the eggs in their nest are never dirty like the ones I collect out of their pen regularly. Still...
Thank you!! One of the REALLY dirty eggs hatched, one did not. The *one* (yes, only *one*) egg that was nest clean is the same one that got crushed on day 24 and still hatched beautifully--in fact, it hatched faster than any of the others.
Maybe I need to try and figure out how to get my ducks...
I am wondering if I should be satisfied with that, or if I should tweak my incubation practices to try and improve it. I set 13 duck eggs and hatched 9, of which one may end up deformed (although it seems to be improving). That's a hatch rate of 60-69%.
Here are my incubation conditions...