I learned at a early age about exploding eggs . Grandma had some geese . Gander never had fertile eggs from them . She always let them set until one exploded . It was then my job to bury the rest . I learned to dig the hole first then gently get them all on the shovel . Hold breath when dumping into hole and cover them with dirt fast .Yep!
Bacteria was incubating and multiplying inside the egg as it rotted. (The incubator did have a slight odor and the egg looked like it was sweating before it exploded. Back then, I did not know those were bad signs. There was hardly any Internet in my early days of teaching, so no BYC to help.)
The bacteria was spread onto some of the eggs and the bottom of the incubator when it popped open. I cleaned it quickly and did my best not to let the eggs cool. But the loss of humidity shrink wrapped the already pipped chicks, the sudden temp drop may have slowed & weakened them, and the contamination of bacteria not only killed chicks but also made my whole lab, classroom, and even the hallway reek.