How Cold Hardy are Jumbo Coturnix?

[Cimmaron]

I am in zone 5. Our average coldest night of the year is -15, but some years we get to -20 or even colder. How much protection do Coturnix need? Can they survive outdoors with a run-in shelter, do they need a completely enclosed coop, heated coop, or do they need to be indoors for winter?

 

[Nabiki]

At those temps, they might need a bit of heat, but for the most part, as long as they're dry, out of the wind, and have shelter, they do quite well in very cold weather. In your case, you might be able to get away with an enclosed area with deep enough straw/shavings for them to burrow into, but I would provide some heat for the coldest days.

The coldest my birds have seen is -7F, but the negative temps didn't last for more than a few days. They were fine for that.