You know, I don't think you'd have to go so far as to recreate it, I think you could just breed in a chicken with similar traits and then cross the offspring together, or breed the offspring back to a different Bielefelder, etc. You'd have something that was a high percentage of Bielefelder...
I'm not an expert, but I did do about 10 incubated hatches, so in my experience, if the egg is rockin' and rollin', it's all good. They are getting ready to pip. Just have them in lockdown mode, try not to keep opening the incubator, monitor them from outside the incubator if possible...
I have the same thing happening, also with an Easter Egger! I got three hens, they are about a year old. I've had them about a month. The previous owner was moving, and the hens were free ranging and laying eggs in hidden nests for a few months, so it's unknown exactly when this issue...