However, there are some that are over priced and inflated, like "super blue egg layers" and other such mixes from MPC that are sooo rare and unique to their hatchery. Really it's like a leghorn and Ameraucana, others here have been making the exact mixes.
IIRC, MPC doesn't breed any birds, they just serve as a central point to get chicks potentially from multiple hatcheries. Don't know where they get the "super blue" or what breed mixes are in them.
Don't chase the chickens, it is mean

Is the ventilation plan to cover the openings with 1/2" hardware cloth? And what about in winter?