Forget what I said about my dismal hatch rate with ducks. I must have figured out the magic formula. In past years, I was only getting about 20% success in hatching. This year, first of all, my drake is hitting high marks for fertility. My fertility rate is well over 95% with my flock. And now my hatch rate is, too!
A few things that are different... the house temperature is more stable. We now have solar hot water heating the floors of the house, keeping internal temps much more stable, which makes the incubator much more efficient and productive. It doesn't have to fight to hard to maintain its internal temp of 101 degrees.
Second, I started a practice last year of lining the hatching tray with damp towels. This raises the local humidity in the hatching tray, but not to the rest of the incubating eggs.
Third, I started to mist the duck eggs daily. I spray a little water on them, just as mama would coming back from a swim on the pond.
Last,but not least, I give them more time to hatch. Chicken eggs invariably hatch on the appropriate date, all at once and with predictability. I have to let the ducks take their sweet time. It can be 36 hours or more from first pip to them coming out of their shell.
I just hatched 23 our of 27 duck eggs. And that was with several hours of the incubator being OFF during that power outage. I think we went 6 hours before we got a generator turned on, and then another 3 hours when the generator had to go back to its home for use for a bit.
We have soooo many ducklings!