Hello,I do not mean to butt in, but I just wanted to mention, I have raised almost my entire flock from shipped eggs. I can not tell you how many hatches have ended up with 0-maybe 2 chicks. It is heartbreaking and has cost me a ton of money. I followed everyone's advise on temperatures and humidities and monitored them to the T, but same results all the time. So I guess I started to get desperate to figure out what is going so wrong, I would start to help some that would pip in anticipation they would not die. In all this experience of my own hatches and observations, I think I have figured out what goes so wrong. Well first of all during lock down I would close the vents or close them more so during lockdown to prevent more humidity loss, but I realized I think this was suffocating the chicks, so I immediately stopped this and utilized other ways to increase humidity. Of course I did have a little better hatch rate in following incubations, but still not great. So next I played around with humidity and how that affected my hatches. And I have to say I have incubated eggs anywhere from 30-60% humidity during day 1-18, then raised humidity up to anywhere from 50-80% during lockdown. From what I can tell I think the sudden increase of humidity is what kills them. I notice if I stay consistant during incubation at about 45-50% humidity maybe 55%, then only raise it up to 60% I have a great hatch. Even on shipped eggs. If I incubate say around 40% then raise humidity to 65% during lockdown it seems like it isn't as good. I really feel like a sudden huge increase of humidity during lock down is not so good for the chicks. I really feel like it makes them die. Anyway, this is just my opinion that I have formed from my own experience, so please do not take me for granted but I really have spent countless nights staring in my incubator just waiting, waiting, waiting, and still nothing. And now I know they are going to come out, I no longer wait, and wait because they actually come out!!