Silkies hatching.

[7daywonder]

I have 10 silkie eggs in an incubator.
1 hatched yesterday which was day 19.
1 hatched early this morning.
Day 21 is tomorrow.
My question is how long can I leave the hatched chickens in the incubator waiting for the others to hatch?
I don’t want to open it and risk the other eggs.

 

[2ndTink]

They can go up to 72 hours without food and water as they are living off the last of the yolk. I don't like going over 48. I vaccinate as I take then out of the incubator so I can't just take them out a few at a time over a day or two, I have to get all or decided to get the oldest out, leave the fresher ones and do a second batch of vaccine the following day for all the later hatches.