Why would people eat them for centuries if they weren’t?
I like the way you think...
The turkey farmer across the road used to give us the double yolked turkey eggs because they couldn’t be sold. If we hadn’t eaten them, they’d have been trashed. Still, lots were trashed. Wish we could get them these days. She’d also give us real milk straight from the cow - oh my! Again, if we hadn’t taken it, it would have been trashed.
I used to also let the eggs dry out aka rot. If the insides stuck to one side of the shell, it’d roll across the floor all wobbly. Great fun.