First, that 21 day thing is theory. There are a lot of different things that can affect when an egg actually hatches, heredity, humidity, how and how long the egg is stored, average incubating temperature, and just basic differences in eggs. I’ve had eggs hatch two days early in an incubator and under a broody. I’ve had eggs hatch pretty much on time from the same flock in an incubator and under a broody. Some people have reported eggs being quite late under a broody. That 21 days is a target, not a firm set time.
Are you counting the days right? You’d be surprised how many people get that wrong. There’s even a calendar floating around this forum that has it wrong. An egg does not have a day’s worth of development 2 seconds or 2 hours after it goes in the incubator. It takes 24 hours of development for an egg to have a day’s worth of development. An easy way to check yourself is the day of the week you start them is the day of the week they should hatch, at least in theory. If you set them on a Friday, they should hatch on a Friday.
I don’t know what is going on with your eggs but don’t panic yet. Give them a couple of more days before you do anything drastic. There is still a reasonable amount of hope. Good luck!
