In regards to whether it's inheritable or not, the only way to really know would be if you were to hatch it's offspring and even then it would likely not show up unless the other parent also had a gene like this. Personally if this grows up to be a hen I would avoid using her eggs in a hatching group.
Were these shipped eggs or locally sourced? I've encountered shipped eggs with birth defects, in that case I have no way of knowing who the parents are, whether they were very closely related, what their nutrition was like, and whether the jostling of shipping may have come in to play. There are many variables when it comes to developing babies of any species.