[COLOR=333333]Hello there and welcome to BYC! [/COLOR][COLOR=333333]

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Sorry you had to give up your babies. I am sure that was pretty hard.
Good luck with the hatch! On lock down day, get your humidity up to 65% or 70% and open all vents wide open. If you have to, put some damp sponges inside the incubator to get the humidity up. Wet them down, don't completely wring them out, but don't put them in there too dry either. Day 21 is only an average hatch date so don't panic if day 21 comes and goes. Sometimes they can hatch days later if your temp was a bit low. When they pip, (break through the shell to breath) they can sit like this for 24+ hours, so don't think you need to break them out of the shell. They are busy absorbing the last of the yolk and detaching from the inside of the egg. And NEVER open the lid of the incubator when there is pipping! You can dry the chicks right up and they can stick to the inside of the shell and die. After they are all hatched and dry, you can remove them. If there are still eggs yet to pip and you know they are viable, you can quickly remove the dry chicks and continue the incubation process.
Here is a nice article from our learning center on hatching eggs...
https://www.backyardchickens.com/a/hatching-eggs-101
Good luck and I hope you get a good hatch!!