Only 2 ducklings

From the batch of 17 duck eggs we put in the incubator last month, only 2 hatched over the weekend. Tonight we cleaned out the incubator and I broke open some of the unhatched eggs. Half had ducklings in them. Sadly, I suspect the power failure we had on Friday, the day before they were due to hatch, killed them. We are considering whether or not to put some more eggs into the incubator. We need more laying birds but time is running out to hatch eggs and have birds mature enough to be raised outdoors on the allotment during the winter. However, if we get the timing right, we could have new birds that start laying in the early spring.