Dany12 IMO that would depend on the amount of green blood in them, i have some spaldings here they are from 2 spaldings that were from a green and blue cross and these birds do fine in the freezing cold and ice here .
Dylansmom has a gorgeous spalding lots of green looking characteristic and he seems to do fine in her fridged temps
Fred has a heated shed for winter, it keeps temp above 45 degrees for him.