Help my hatching duck are all dying!!

So I have hatching ducks and they are all coming out with their yolk sack unabsorbed and they keep dying for some reason. Most of them where an assisted hatch and would have made it out on their own. Can someone please help me save the few I have left what can I do to help them? I have them in the incubator drying out but they are not getting fluffy they are drying hard and I’m afraid they won’t be able to move pretty soon! I had mixed batches which I realize now was a huge mistake I had put a batch in and two weeks later put in a second one. When the other batch hatched two weeks ago the humidity shot to to 85% and I’m afraid the high humidity affected the still growing ducks. I have 5 that have made it to the brooder with the other ducks and are doing great but the remaining in the incubator are not well. Some can’t stand and are very weak. One was dried out and fluffed up but couldn’t stand I put him in a sock and into a glass under heat lamp. I take him water in a dropper. Please help I have had to bury 6 dead ducks since yesterday I will attach photos of the ones I still have alive. Thanks you!