We used a still air home made incubator to hatch duck eggs, and tho we had to monitor humidity and temps carefully, by cracking the lid a bit, spritzing eggs to raise humidity, we found the eggs to be way more tolerant of change than chicken eggs, and hatched out 14 out of 16 in a staggered hatch over a period of 3 weeks. Couldn't do the lock down, weren't experienced at all, and learning on the fly with BYC forums. Knowing more now, I wouldn't do a staggered hatch, even tho we only lost 2 at an early stage. Their shells were very hard tho, and most needed a bit of help once they pipped. Warm washcloth, a bit of hard outer shell picked off. Good advice on this intervention in BYC forum.