quail have hatched

[cresent moon poultry]

my corturnix quail started hatching yesterday on day 18nth of incubation. when should i take the ones that did not hatch and help them hatch or find out why they did not hatch. thanks in advance

 

[WVduckchick]

I would candle any remaining eggs when you remove the chicks to see if any are just delayed or if they stopped developing.