Some can be clumsier than others, but all hens walk on the eggs. That’s broody hens getting on or off the nest or hens laying eggs. Practically always when I find an egg broken, punctured, or crushed, that specific egg had an unusually thin shell. You can candle the eggs before you start. If they look really porous don’t star them.
When that egg broke, did it get egg goop on the other eggs or maybe her belly feathers? If you are only on day five and those remaining eggs have goop on them, I’d toss them, clean the nest and hen up, and get some more eggs. I’ve had that happen before and that hatch was a total failure. On the other hand, if they do not have dried egg goop on them keep going. That egg goop allows bacteria to get inside them, which is not good.
Depending in how dark shelled those eggs are and your candling technique you might be able to see movement or development when you candle, you might not. With my dark green eggs and candling technique I’m lucky to see much more than the air cell for quite a while. I never toss an egg early in incubation because of what I do or don’t see when candling, even the eggs I can see into pretty easily. I use CT’s method and smell them. If they start to smell like rotten egg, get rid of them quickly. As long as they don’t smell, I let them go.
