Some of my hatches are totally over in less than 24 hours of the first one coming out. I’ve had hatches drag on or well over two 24-hour days. That’s both in the incubator and under broody hens. When a hatch drags on like that it’s mainly due to differences in individual eggs, not something you did. I can remember one hatch a few years back where one chick hatched late in the day. I finally saw a pip just before I went to bed the next night. 24 hours and nothing. Yes, I was getting worried. The remaining 16 chicks were all hatched before lunch time the next day.
There are a lot of things that affect how close to 21 days the egg actually hatches. Average incubating temperature is a big one but there are many other things that have an influence. That’s probably why Nature has the chicks absorb the yolk, they can live off of the contents for three days or more so the early ones to hatch can wait on the later ones without starving or dying of thirst. That’s why they can be mailed.
Since your chicks hatched within 24 hours either side of that 21 days, I consider your hatch spot on. Don’t mess with the settings on the heat.
It can be hard to know when the hatch is over because of the way hatching can be spread out. You do not have to take any chicks out until a full three 24-hour days have passed from the first one hatching. Many people do though, they just pop the incubator open and grab a chick whenever it has dried off and they hardly ever shrink wrap an unhatched chick. Shrink wrapping can happen but it’s not as common as you’d expect from a lot of comments on here. If the egg has not external pipped you should not worry about popping the incubator open long enough to grab some chicks. Even if an egg has external pipped you probably won’t cause it to shrink wrap but the risk goes up. I don’t open the incubator after lockdown unless I have a good reason, which for me means some kind of an emergency. If I need to open it I do. The risk of actually shrink wrapping a chick is so low that I’m willing to take that risk if necessary, especially to save one that has hatched.
With all those chicks in there chirping away you will not be able to tell if an unhatched egg is peeping. The way they move around you probably cannot be sure if an egg is moving on its own. The way I determine when to take the chicks out is to wait several hours after the last one has come out and the chicks have pretty well dried off and are moving well. In high humidity like you are seeing that can take a while to dry off, you may have to settle for still a little damp. Don’t let them get a chill on the way to the brooder. If I don’t see an external pip on another egg I take them out and put them in the brooder. I usually put the lid back on and wait another day before I clean out the incubator but I cannot remember ever getting another one to hatch doing that.
A test you can run just before you toss the unhatched eggs is a float test. Put warm water in a basin and put the unhatched unpipped eggs in it. If the egg moves on its own there is a live chick in it, put it back in the incubator. At this stage if the egg does not wiggle on its own there is nothing alive in there. Some people candle the eggs before they toss them but with my dark green eggs candling looking for movement is problematic.
Congratulations on a good hatch, you are now a pro.
