I just want to mention that, in my limited experience, it really is better to have some sort of ongoing air exchange in the incubation container. I've tried using small airtight plastic containers and opening them weekly or so for air exchange as I've read others suggest, and I've tried using the small squarish deli containers from the grocery store (the things potato salad and such come in) that don't seal tightly, and the deli containers definitely make keeping the eggs at the right humidity easier. I have a pair of eggs in an airtight container right now, and while these eggs were odd-looking when I got them -- both were dented -- they "undented" and were looking good, but now appear discolored, so it could be the eggs, but it could also be too much humidity and/or not enough fresh air.

Good luck Mle!