Any standard breed with a rose or pea comb should do well in your winters. Wyandottes are great egg layers, foragers, and have mild temperaments. We love our four.
I don't know anything about them, but since you're in Iowa, a good heritage breed might be the Iowa Blue. It was developed in the early 1900's especially for your state's weather.
Regardless of the breeds you finally decide on, you may be able to find local farmers willing to sell you some day-old chicks or some started birds, which may possibly be less expensive than getting them online. You also then have a local poultry connection, usually with a wealth of information on getting "chicken stuff" locally, (best place for feed, best avian vet, etc.).
You can order a mix of breeds. Our flock last year from McMurray was ONE of each breed listed. We ordered all pullets and ended up with 2 cockerels ...
Pullets-
Silver Lakenvelder
Golden Laced Wyandotte
Silver Laced Wyandotte
White Wyandotte
Columbian Wyandotte
Araucana/Americana
Dominique
Barred Plymouth Rock
Partridge Plymouth Rock
White Plymouth Rock
Rhode Island Red
New Hampshire Red
Jersey Black Giant
Buttercup
Ancona
Buff Orpington
Delaware
Silver Spangled Hamburg
Golden Penciled Hamburg
White Faced Black Spanish
Silver Grey Dorking
Speckled Sussex
Rose Comb Brown Leghorn
Cockerels-
Golden Campine
Single Comb Light Brown Leghorn
We declined the free exotic chick. McMurray sent us 2 White Plymouth Rock pullet chicks instead of the 1 we ordered. We got our day-old chicks in June, so no extra "for warmth" birds were added.
Good luck and have fun!
regards,
keljonma
if edited, probably for typos...