Well we know what breed a Rock is so there really isn't confusion there.
Want to get into angry people and insistence that the hatchery/feed store is correct? Look at the EE (americana or whatever each one calls them) - Ameraucana and Araucana issue. When my mom was a kid back in the 50s and 60s, Grandma had got hatchery Araucana. They laid nice blue/green eggs. Color was pretty consistent between birds. Mom says they looked nothing like the hatchery birds I have now. The modern hatchery EEs I have are wonderful girls for eggs. Much better than my ameraucana. Even at 5 years old, I'm still getting about 3 eggs a week from each of them (that isn't broody).
I am trying to bring back those original hatchery "Araucanas" that are technically Easter Eggers but not the mutt Easter Eggers. I loved them so much and kept a flock for many years not knowing how impossible they would be to replace when we moved across the state. I am using a Quechua rooster over two hens that I like so it will be fun to see what we get when the chicks are grown.