That's cool to know. I always thought of TSC or similar birds as mixes to some degree and that's what made them "hatchery quality". So I figured all my birds are somewhat mixes. But I guess not. You learn something new every day.
She's from Tractor Supply, so probably. I'd like to know what she is mixed with, as our other Plymouth Rock had something closer to a typical Plymouth Rock comb, but she too was probably a mix. I have a picture of her as my first entry.