Incubating Call ducks

[Chloe]

Hi guys Im fairly new to chickens but I have hatched a few batches successfully and am now trying Call ducks, basically I really want one as a pet anyway so anymore than that is a bonus. So they are in an rcom suro king and today is day ten and I have 9 fertile out of 12 so not doing too bad thus far! From what i have read these ducks have difficulty hatching, so is there anyone out there with tips for a more succesful hatch? ie humidity, day to stop turning and anything else!