Movement but no pip, now no movement

[brittonia18]

Today is day 21 of my chick incubation. Yesterday (day 20), one of the two eggs I have would move occasionally when I played videos of chicks chirping. It made no sounds, only moved. I figured today I might see a pip, but still nothing. I tried to play more videos to make sure they're alive and giving me signs of movement, but they haven't moved at all. Should I be concerned? How long without a pip should I open the bator up?

 

[brittonia18]

I finally heard chirping last night but when I woke up this morning there was still no external pip. She did chirp this morning so I know she's okay. But when should I intervene and help make a hole if she doesn't? It's been about 12 hours

 

[brittonia18]

Anybody ? :/