When I went to lockdown the incubator yesterday, I discovered that a few of my Guinea eggs had pipped several days ahead of schedule. After >24hrs with no further progress, we carefully removed some shell from one and placed it back in the incubator. It had not gotten through the outer membrane. We later opened the membrane (only a very tiny amount of blood in one area that we avoided). The chick was nearly lifeless and had not yet absorbed its yolk sac!!! Why then had it started hatching the day before?! We left the others alone. FYI, temp during incubation was 99-100, though one day it got up to 102 briefly. The humidity has been around 50-60% during incubation, but we bumped it up to 70% at lockdown. Also, unfortunately we learned that we had the eggs in the turner upside down for the first 10 days. We righted them but worry this caused issues.