Day 22-23 4 chicks out and healthy BUT- one egg I hear peep-peep but no pip. What should I do?

[LaLee]

I want to help by making an air hole chip but not sure if this will help. It is an EE chick egg.

 

[Yorkshire Coop]

All depends how long it's been peeping in the egg? Generally if they are peeping in the egg they are fine as they have oxygen. When it's starts getting low and the c02 high this should kick the chick into externally pipping. This chick may just need more time not all hatch at the same time. 21 days is just a guide. Have a read of this article it's an excellent read and very informative ~ https://www.backyardchickens.com/a/step-by-step-guide-to-assisted-hatching

Good luck hope it gets a wriggle on for you soon