Help! Gosling chirping in shell not due for 9 days

[galen54]

I am incubating a sebastopol gosling, who is not suppose to hatch for 9 days. this morning he/she started chirping in their shell. How long do I let them stay in the shell without helping them?
Thanks

 

[sonjab314]

Candle the egg and see if he has pipped into the air sac of the egg

 

[kuchchicks]

How can you tell if internal pip is done when candling? Does the air sac look gone?!