Congrats, being that this was your first hatch, you did a wonderful job!

Sorry you had some troubles however this was a good learning experience. Being that this is day 21, I think they hatched a bit early which tells me either the temp was a bit too high or the eggs started to develop before setting. And this alone could have caused the troubles. Give the other eggs a couple more days and if nothing is happening, you can pitch them out, they are either dead or infertile.
Enjoy your new babies, they are adorable!