150 years ago they may not have had certain breeds in colder climate areas.
, too. There is a wide, wide selection of cold-hardy breeds available. And note that when people say you don't necessarily need heat, they usually qualify it with "for typical chickens" i.e. not horribly out-of-place breeds.
What did they do back 100+ years ago? What about water? What about freezing eggs or chickens? What breeds did they normally have in the central plains or Canada.
Water? They brought pans or buckets from the house multiple times a day.
Freezing eggs? Not much of an issue - eggs don't freeze til IIRC about the mid 20s F plus which it takes them a good long time to get that cold (remember they start at 'hen temperature' and are typically half-insulated by the nestbox bedding they're lying in).
Also, remember that back then, just like today, there were LOTS of measures that help prevent the coop from getting as cold as the nightly lows outside.
AFAIK breeds that were common a hundred or a hundred fifty years ago, as general farmstead chickens,
in colder areas, were things like Javas, Dominiques, Rocks, Dorkings (game types were also common in that era but I honestly have no idea whether they were common in cold areas). Plus of course by that time fancy breeds such as Brahmas, Cochins, Wyandottes were reasonably widespread, although more as a hobby than as Yer Basic Farm Chicken. There are many other breeds that are common today that also make good cold-weather chickens, of course (buckeyes, chanteclers, and orpingtons come first to mind).
Yes, some people would have some chickens lose some comb points or toes to frostbite. Avoiding that is largely a matter of good coop design and keeping an eye on what's going on. Also since we now have electricity freely available we can put a lamp on during especially cold nights if we think we have to (which is a lot different, IMHO, than regularly using a lamp or trying to 'heat the coop' as such). And of course the more you want to avoid frostbite risks, the more you want to choose your breeds intelligently.
Really, the comb is the most vulnerable part (assuming a wide roost) -- beyond that, look at the other birds that do just FINE in very cold temperatures. Chickens are birds. Chickens have coped with winters without heat (in a good coop, with good management) for centuries. They're still basically the same chickens today
Pat