Day 5, and I just candled a few of the 39 eggs I have in two incubators. I couldn't see much yet; enough doubt about a few of them that I just put the lids back them all on and put my light away. I could just *barely* make out embryos and blood veins in some of them, and air cells - when I could find it - were very tiny, about nickel-sized. I'll try again on Day 7.
I'm keeping logs on these eggs - weight, air cell size, and tracking temp and humidity 3-4 times a day. I love the little Kebonnixs incubator - always constant temperature and humidity, and turns the eggs completely over through its rotations. Hands-free except to add water to the external reservoir once every day or so. My IncuView, on the other hand, is a hassle; temperature fluctuates, and I have to watch humidity very closely. Have to take the lid off to add water internally. Also it only turns them about 1/3 right or left, so every night I turn them all over to a different marking I've made on the eggs.
Live and learn. I see another new incubator in my future someday - but now I know exactly what features I'll be looking for.