That is a wide spread. If you rotate the eggs and your humidity has been good, I'd have to say it's something with the individual egg. It is interesting. Normally a hatch is done w/in 48 hours of the first hatcher. Of course there's always exceptions but 19-24 is unusual.I'd be surprised if that was the case- I moved around the eggs all through incubation and especially after lockdown. 3 eggs does the day after lockdown and one died on day 22. All before internally pipping. There is 1 left that is just starting to hatch on day 24. So first hatched on day 19 and last on day 24. I haven't read that happening before. I guess every hatch really is different. It seems like alot is the egg more than anything. After this hatch I know bantams do hatch early but no need to do early lockdown. They will just hatch earlier like day 19. But it is possible for an egg to be very late even after all hatch. Very interesting