I have been having issues where a lot of my eggs have been quitting within a few days of hatching. I assumed it was an issue with humidity. However, I did notice that whenever I hatched eggs in a carton they did much better than if I laid them on their sides (these were eggs that had been upright in an auto-turner through Day 18). They were shipped eggs and a lot of them had unstable air cells. I am now thinking that the unstable air cells could lead to problems if you lay the eggs on their side? Just an observation I had. I think I will stick to hatching in the carton now, since I've had better luck that way. The only problem I had was one egg seemed very late to pip, but I picked it up and found the pip on the small end. Fortunately I found it in time and it did okay after I took it out and laid it on its side.
Another issue I noticed is that with the shipped eggs, there has been a wide range of air cell sizes within a single batch. I assume the more dried out ones had been stored longer. So it's hard to determine the "correct" humidity to use when you have to accomodate eggs that are not uniformly evaporated.
Sorry I can't answer your question about sebrights in particular. Just thought I'd share my experience.
