Help Day 19 incubation quitters

[nnewberry]

My chickens keep quitting on day 19. I set 33 eggs to hatch on day 18 and I only had 9 hatch. I investigated the eggs that didnt hatch and they all quit around day 19 or 20. I know this because of the embryo development. They didnt drown when they did the internal pip because they didnt quite make it that far

 

[sumi]

Here is a troubleshooting article that may help: https://www.backyardchickens.com/a/egg-failure-to-hatch-diagnosing-incubation-problems