I actually read about someone who kept buttons and pheasants together in a large planted aviary. Not sure what kind of pheasants though. Long story short, the buttons stayed out of the way of the pheasants but when the buttons hatched chicks the pheasants gobbled them up like little snacks. And so the owner decided to separate them.
Well.. I live in Denmark. Our winters go as low as -20 celcius. Might not have been below -15 this year. And I had a trio of buttons in an outside aviary which did very well. The aviary is around 3 by 10 ft and the majority of it was enclosed in some way, leaving only the door fully open to the elements. I built 2 boxes with open fronts slightly off the ground at one end, put wood shavings and straw in one and placed a couple of spruce branches in front of it. That was all the insulation they had.