This is critical. BG knows many rookies that have suffocated their snakes by not giving them air later in incubation. It's one reason BG likes to keep a couple small holes in his boxes. As long as there is not too much air circulation in your incubator, they won't dry out too fast with a couple small holes. BG recommends this(small holes) for people that are very busy and may forget to give their eggs air. Just make sure they don't dry out. That's almost as bad.