EEs from hatcheries are not crosses but rather descendants of the original landrace stock. And they are often chipmunks but not always.EE's can be different crosses, thus their slight differences as chicks.
EE and wellie both are chipmunk but legs color should tell the tale...
...wellie have yellow legs, EE have greenish/slateish
I don't have the old pictures handy but I had two that looked a good bit alike as chicks. Typical chipmunk markings in slightly different hues. One ended up chocolate brown with black patterning and a salmon chest and the other was such a light red she was almost buff. You really might be surprised.