I bet they're lilac/lavender. This is a lavender ancona. You can see how it just looks kinda gray and it's hard to tell there's chocolate involved - but there is.
Actually, them being male makes it MORE unlikely. A drake has to get two copies of chocolate, one from each parent, in order for it to express. A female needs to get only one.
That's why I was saying it's weird you have blue females - they should be lilac, actually, since if their father was...
Well that's odd, lol! Are you sure dad was a fawn and white runner? All his daughters should be chocolate in some form, if he was fawn and white.
Also, the drake shouldn't be able to be fawn and white unless both his parents were chocolate in some form. Which is possible, since the pekin could...
The ducks in your avatar are blue bibbed/pied, by the way :) Gray bibbed would be a whole other thing, since in ducks 'Gray' is the color name for a duck that looks like a wild mallard.
Ducklings are slow hatchers; sometimes they take up to 48 hours to start to zip from the time they pip :) So for now it's probably safe to leave them, since they can breathe fine. If it gets to be more towards the 48 hour mark, that's when you might want to consider assisting.
What breed are they?