Why don't you try to get a good thermometer and hygrometer, stick them on their own in the incubator (if it hurts you too much right now to put more eggs in, you don't have to), and try to see what your incubator really is at? Babies that die in the last days of incubation... Generally it means you have a problem that is fixable, you just need to figure out what it is. Almost always it's humidity, from my experience... Did you notice that the ducklings seemed swollen at all? With excess humidity, the babies will appear swollen, along with having smaller air cells. From your picture, I
have had eggs with air cells about that size hatch successfully, but from the looks of it... I'm thinking that baby was attempting to internally pip, and then died. If your issue is a humidity issue, they will die when attempting to break through the membrane and breathe, as they will be met with a lot of fluid. So, from the looks of it, the air cell was larger due to this process, thus at its largest during the incubation process, but it should have been at least that size prior to pipping, and then would have grown to about 1/3 to nearly 1/2 of the egg during pipping.
My condolences for losing them, though.
It seems you've been through a lot. I know the feeling. Raising birds, or for that matter any animal, is never easy. You lose more than you save in the beginning. But if you learn from your experiences, let them strengthen your resolve rather than weaken it, you can do a lot of good in the future. You have a great incubator from the sounds of it. You just need to figure out what's going on in there and try to fix it.
