Hummm... will it hurt them if they are alive??? I candeled one silkie egg... it is black but my light is horrible so that is all I can tell... the air sacks seems small.... the one I opened had piped in the middle of the egg and was no where near the air sack...it still has a good amount of blood vesslies but I have its beak out so it can breathYou can try doing the float test or you can candle them to see if they're alive.
What did the air cell sizes look like?
Did the others hatch on day 21?

So, if it is black inside and makes no sound, leave it for 24 more hours and re-pete...Hold them against your ear and tap them. Listen for a response from the chick. I check my overdue eggs like that and by candling. If I don't see anything when I candle and tap I leave it another day.
if it is black AND peeps help make a pip around beak and leave and check its progress and only help if no progress is made after sevreal more hours??