Truthfully, you could say most chicken breeds are mutts, by that standard. Wyandottes have Cochins in their background, but that doesn't make them mutts. Why? Because they do breed true now that the breed is established. If you would post pictures, we would probably be able to help you decide if you have standard colors. This is an issue that seems so confusing to people, but if you sell EEs as the Ameraucana breed, it just perpetuates the confusion, IMO.