My last batch that we hatched a couple weeks ago, we had a "surprise" baby on day 25. I had left the eggs that didn't hatch on day 21 and 22 in the 'bator and was about to get rid of them when I saw a pip in one. He didn't take long to get out once he pipped, and he's been fine ever since! However, if they don't hatch in the next day or two I would say they're done... I know how disappointing it can be, but this is a learning experience for me each and every time!
https://www.backyardchickens.com/a/hatching-eggs-and-raising-chicks Great information here, and I've learned a lot from this site the past year.
I wish you all the best!
