Does the bottom of the machine look like shiny plastic? Chicks need traction in this wet environment, when they slip they can easily get splay legs, a serious pulling and slipping of tendons.As soon as I got the notification for your reply, one had just pipped! I don't know if the incubator I got has a no slip bottom, I have a KEBONNIXS 12 Egg Incubator. How much of a threat will the egg be from now until 24 hours after the first chick hatches?
Congrats on the first pip! The others should be right behind this one. Rotten eggs can pose health issues to the hatching chicks, there is a lot of bacteria in that bad egg. You might reach in quick like and remove it, have a water spray bottle handy (with warm water) and quickly spray the eggs lightly after you open and remove the bad egg. The spray will help replace and humidity lost.