It's very common for hatcheries to mix them up. McMurray even says up front they deliberately mix them up for a "varied color flock".
So yeah.. hatchery stock are in a way like Easter Eggers. Nice heavy and productive birds(which is really more their goal- more eggs to set, more chicks to sell) but with a lot not even matching the "proper breed standard" as for color and some other things.
I don't know why hatcheries produce a lot of birds obviously not pure for the naked neck, with the huge bowties. It's so easy to pick the pure ones out and make a flock pure-breeding for the naked neck trait, at least.
However, it's not just hatcheries, it's also very common for private persons or backyarders to mix them and/or not select them out for pure breeding. Birds matching the show standard are not very easy to find, actually.
Someone suggested(and I like the idea) maybe hatchery stock could be called Turken with the show standard ones being called Naked Necks.. in the same manner of EE vs Ameraucana.
In any case, both Turkens and Naked Necks are very nice birds.