Why is it that all my fertile duck eggs have veins only on one side?

[MROOD]

So I have 6 duck eggs, I placed them in a incubator and 4 of the eggs have grown veins, but only on one side

When I candle the eggs I can clearly see a 1 inch embryo clearly moving around like its wiggling continuously

So it seems its alive but the issue is when I turn the egg, on one side its completely empty, no veins clear and empty

Yet the other side of the egg have fluids and the embryo, it seems its stuck on one side, if I roll the egg the liquids and embryo doesn't move on the other side, its like its set in place within half the egg, gravity not moving the contents.

All 4 eggs are like that, my machine is automatically set to turn the eggs every 2 hours, but it looks like they haven't been turned maybe?

I would of thought the liquids and embryo would of been free moving in the whole egg rather than just half of it

Will these eggs survive? its day 10 and 18 days to go, I mean if its stuck whats the point of turning the eggs because wouldn't that cause harm to the embryo?

Ive also got 8 tiny chinese quail eggs in the same incubator, they are the size of a grape but smaller, thats ok right?

 

[Susan Skylark]

Quail eggs get sludgy days 4-6 (16 day incubation), this is perfectly normal, just give them thirty seconds after turning the egg, the embryo will gradually ooze to the top. Scared me the first hatch too but every single egg has done it. The veins radiate out from the embryo and both sit on the yolk, this whole thing moves, sometimes slowly, as it has a different viscosity than the white. A sloshy egg usually means a dead egg, sludgy is good!