It's a very silly practice of these organizations to call a breed of chicken another name when it doesn't meet very specific and strict standards. It's like mixing brown and white Leghorns and calling them shinflutes
Purity-spiraling elitist nonsense
When two Ameraucana of different colors mix and produce a color not recognized officially it's considered an Easter Egger. It's a slang term that can refer to both pure and mixed breeds