Ameraucanas (Spelled that way) are an APA recognized breed of chicken. They have an SOP, and always have muffs, beards, pea combs, slate shanks, and lighter bodies with longer necks. They come in distinct, recognizable colors (including but not limited to: blue, black, splash, wheaten) and breed true. An ameraucana x ameraucana is always an ameraucana. They always lay blue eggs. This chicks are more expensive than easter egger chicks, usually at about $20 per chick.
Easter Eggers: Mutts/hybrids usually created from ameraucanas that will often lay green or blue eggs. These guys usually have pea combs and lighter bodies, and will sometimes have muffs, beards, or both. They come in loaaads of colors that aren't recognizable and usually have crazy patterns. They can lay blue, green, brown, tan, or pink, and won't breed true.
Americauna: Easter Egger
Ameracana: Easter Egger
Ameracauna: Easter Egger
Araucana: Another separate breed that, in America, are rumpless and have ear tufts. They have pea combs, come in distinct colors, breed true, and lay blue.