I never bought into the egg thing. There’s clearly a distinct cell in the center that’s going to divide and grow inside the egg. The egg itself isn’t undergoing mitosis.
It turns out the oocyte is the single cell inside the egg, which for birds is significantly larger than a typical cell. So in that respect, the cell in a bird egg is very large. However, compared to the egg itself, it's tiny. The yolk and whites in the egg are all to provide nutrients as it grows, if fertilized.
From Wikipedia:
> The yolk is not living cell material like protoplasm, but largely passive material
Wouldn't this be true about any organ?