We're moving all our peas inside for the winter tomorrow night after dark.I know some peoples aviaries has small buildings peas can go into when the weather is bad,but their peas still stayed outside and roosted on their perches depsite the sub zero temps with blowing winds. My Pea building isn't heated but the perches are all 2"x6"'s laid flat so the bird can keep it's entire foot covered when they are sitting down on the perch,preventing frostbite. We had many days here last year in Illinois that was below zero,a few times with wind chills 25 below,,nothing happened to any of ours.I think my main concern here is always the wind and we are in a true prairie area here,no real windbreaks for miles,and nothing to slow the howling wind down. Yours should be fine if they're out of the wind,despite the cold temps coming,which we won't realize until Thursday here