Hi Dave, the misting, for me, it imitates the mother duck coming back damp and wet to the nest after water and eating the few time(s) she does a day....It helps keep the shell moist.....
I sprayed mine twice daily ....Others spray waterfowl once a day or not at all. This can be done with a small amount of slightly warmed water. You can then leave the incubator open for a minute or so afterwards. Sometimes this can be of benefit. If you do it, start at day 7 and do not spray after day 25. The actual consequences of spraying are " It changes the membrane of the egg so a greater percentage of moisture is lost during incubation. Ideally, a duck egg looses about 13% of its weight between the time it is laid and day 25 of incubation. Loosing significantly more or less than this reduces hatchability. " So you don't want to soak them only a light spraying...if you choose to go that route! Hope the eggs are doing well! Nancy