After thinking about it more, I'm sure there is no need for air exchange until they hatch. I don't see how air could be exchanged through the shell of the egg. This just proves it I guess!
I open mine here and there throughout the process to add more water when needed. I do like to candle when I put them in to see if there are any problem eggs. I also like to candle again at the end when you can see the pattern through the egg, only because I think it's neat![]()
Checking on them all the time won't do anything for them unless there is a humidity issue. If you aren't sure about your humidity you should keep an eye on them. I suggest going substrateless so you don't have to worry so much about humidity. It's just easier to soak the substrate and get your eggs off of it.