The terms for this breed Araucana, Ameraucana, "Easter
Egg Chicken" - have been used interchangeably - though there are differences in the Araucana and Ameraucana breeds.
The Araucana breed is usually rumpless, as well as differences in the cheek muffs and "wings" at the ears.
The Ameraucana breed started with the chickens from South America and were crossbred to ther chickens. The blue and
green colored eggs carried through.
Our Ameraucana chickens occasionally produce rumpless offspring (we have a Delaware/Ameracauna cross that is rumpless).
Our Ameraucanas do lay both blue and green eggs.