On a scale of 1 to 10 (1 the lowest, 10 the highest) how hard is it to hatch call ducks. I have heard they can be difficult. I plan to mist and cool during incubation (following Storey's Guide to Raising Ducks) and use clean hands. I am also not cleaning the eggs off. I will be using 9200 Little Giant Still Air incubator. Just want some opinions...