I'm sorry, I don't see any sign that those are developing. For comparison, here's some of my day 17 eggs.
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Even in a darker egg where you can't see a lot of veins, you should have a large air cell with a sharp border, and some parts of the egg that are completely blocked by the growing embryo.
Do you have any eggs that look like that? If you don't have any eggs that have developed at least a bit, double check your incubator temperature and that the eggs you're using are fertile from a flock with a rooster.