I posted earlier about trying out my homemade incubator for the first time with a dozen of my own mixed chicken eggs. About a week into the incubation period I inherited a Pekin duck on a nest of 15 eggs, which she abandoned, so I popped them into the incubator too. We are now on day 12 of gestation for the chicks, and I'm guessing the ducklings are at least halfway through development (the previous owners had no clue the duck was setting or when she might have started). I discarded one duck egg that showed no movement after three days, and last night I pulled a second cracked and repaired one that the mother duck had stepped on the first day. It had been doing fine until the last 48 hours when it quit. Everyone else is doing well, but one of the duck eggs has a large air sac on the side of the egg rather than either end. As the baby grows I'm getting more and more worried about how it's going to get out of there and whether there is anything I can or should anticipate doing to help. Frankly, I'm surprised it's survived this long since it seems like such an anomaly. Does anyone have any experience with this? My other concern has to do with lockdown and increasing the humidity in the incubator. Since I don't know with any authority whether the ducklings or chicks are due to hatch first, I'm not sure how to handle this. If I increase the humidity to 70% or so to accommodate the ducklings, won't I be compromising the chicks if they're not ready to hatch? Since the ducklings' hatch date is a mystery, how can I even start lockdown unless nobody starts pipping until the chicks are due? I hope I'm making a mountain out of a molehill, but I would hate for them all to have come so far and then have something tragic happen due to my ignorance.