I'm a dog breeder and this baffles the crap out of me. Animals with standard flaws and faults are genetically still their breed. They just don't fit the standard. a tuftless Araucana is genetically still an Araucana, still has the genetics for blue eggs etc they just have a flaw. AND in South America there ARE Tufted Araucanas, tuftless Araucanas, crested Araucanas, smooth headed Araucanas, Rumpless Araucanas and tailed Araucanas
Dog breeding is prescriptive - you keep pedigrees, and the breed tells you what the animal "IS".
Chicken breeding is Descriptive. Its different.
This is because the showing process developed for very different reasons - dog showing has its roots in the aristocracy, chicken showing has its roots in livestock auctions.
Saying "This bird is an Aracauna" isn't saying "This bird has the genetics of an aracauna, comes from a long line of aracaunas, and will produce aracaunas" - its saying "This bird fits the breed description of an Aracauna".
In APA shows, it is perfectly legal to show birds as one breed despite neither of their parents being of that breed. It is perfectly legal to show a crossbred bird as one breed, and crossbreeding is not uncommon to improve specific traits. If you breed, say a Barred Rock and a Delaware together, you're going to get a barred bird that could be shown as a barred rock (atleast on the hen side).