Help!!! It’s day 21 and our eggs aren’t hatching!

[AnimalPerson]

This is our first time hatching chicks. They’re in an incubator and the temp is set at 99.5, and humidity is around 64-68. They were very active and wiggling around on day 19 but they still aren’t peeping and are not wiggling very much! It’s day 21 and still no pipping! We have 4 blue eggs with pretty thick shells and we also have a small brown double yolker. Why haven’t they pipped?!

Also, do the eggs wiggle when they try to pip?

 

[Sapphire Sebright]

Sorry that it's been so long -- did they hatch?
The chicks might take a day or two after pipping to fully come out -- eggs don't always take exactly 21 days to hatch, just like how childbirth doesn't always happen exactly nine months after conception.
I think that the egg might move a little while the chick is trying to pip -- the little thing is putting a lot of energy into escaping the shell, after all, so the egg could rock and wiggle some.