I'd guess they're purposely inflated to cut down on people asking to buy them
“We don’t want to do it, but if you are really going to pay this, we’ll make it happen.”
I was quoting some wood deck and lawn work this spring. I had four people come out to quote, and two gave me fuck off prices about 3-4x what I eventually paid.
EDIT: for reference on good eggs, I’ve found duck eggs to be superior to chicken eggs.
Especially if you're interested in hatching ducklings.