When do you think Easter Eggers first started being a thing?
As far as I can tell, for quite a while, the chickens being sold that came from Ameraucana lineage were being CALLED "Ameraucanas," not Easter Eggers.
Example from McMurray Hatchery:
"We have been breeding Ameraucanas since the...
Not quite how I would put it.
I would say that "Easter Eggers" are any chickens that lay blue or green eggs but do not belong to a recognized pure breed.
It doesn't matter whether they are descended from Araucanas, or Ameraucanas, or Cream Legbars, or directly from the original blue-layers...