Please help! We have been incubating in a turner & transferring to still air at 25 days - Welch Harlequin & Khaki Campbell duck eggs. We candle at 7 days and again at 15, once more at 25 when transferring. We have several babies - however - our last batch of 15 only hatched 4. All 15 were active wigglers when transferring to still air. 2 pipped and bills out and died. 4 hatched (overnight). The rest - fully developed and through the air sack but not the shell - never hatched. Fully formed perfect babies. Is it the humidity perhaps? I sanitize the still air between hatchings. It seems they are not able to get through the shell and just suffocating in there. Poor things. What should the humidity be in the turner and what should it be in the still air? Thanks for your advice.