Oh I would be too scared - I know in theory what to look for but I wouldn’t trust myself!Mainly me
I've just been outside in the dark candling the eggs and it looks like there are two chicks and one non-starter.
What will you do? Replace the non-starter with a fake egg? Leave it a bit longer to be sure (it won’t go rotten for weeks). Maybe the ladies will figure out it isn’t viable and reject it if their own accord.