First let’s talk theory. An egg does not have a day’s worth of development two seconds or two hours after incubation starts. It takes 24 hours for an egg to have a day’s worth of development. Instead of thinking “days”, think “days of development” when you count. An easy way to check your counting is that the 21 days of development are over on the same day of the week you set them. You started them on a Monday, they should hatch on a Monday.
Now let’s talk real life. There are a lot of different things that can effect when an egg actually hatches; heredity, humidity, how and how long the egg is stored before you start, and just basic differences in the eggs. A big factor is the average incubating temperature. If the incubator is a bit cool, they can be late. If it is warm they can be early. I’ve had eggs as much as two days early both under a broody hen and in the incubator. I’ve also had eggs pretty much on time with both a broody and in the same incubator. Some people have had hatches a few days late. Each hatch is different and usually I don’t know why.
Good luck with your hatch. In any case, you are getting close.
now fingers crossed the rest will to
