It could also be an EE crossed with something else...thus giving you a different look, but still the blue eggs. Like a Dark Cornish EE mix or something...Then again, it would be easier to carry over the blue egg laying if the hen in the breeding laid white eggs and the male was the giver of blue it seems to me. Alot of times when you mix a blue egg layer with a brown, you get a green layer...But if the mother was a cornish that laid very light brown eggs, then it stands to reason that a few chicks out of that hatch could possibly also lay blue eggs. I'm guessing cornish, because they just have a look to them (they might be one of the only breeds I can recognize right away, them and Buff Orpingtons) Anyway, I'm also guessing Cornish because they have those same markings, and they go broody fairly often, and also usually lay a light brown egg.
But before I go off the rails with cornish, how big is she? Like medium, small, large?