duck egg issue or maybe not?

[larcie]

I've kept chickens for a few years however ducks are new to me.
I've noticed the ends of some of my campbell duck eggs seem different, more see through than the rest of the egg but not actually see through. The shells are strong,well shaped, smooth, no cracks and look fine when opened.
What's wrong with them? Are they safe to eat and sell?
Thanks.

 

[BSL Egger]

Nothing seems to be wrong with them. It is probably just some heritance that they got. They should be safe to eat.