Too cold for outdoor aviary for these birds?

[Luvbirdlover]

I plan to put zebra finches, cockatiels, budgies, canaries, diamond doves, and lovebirds (separate aviary ofc) in some outdoor aviaires.
In the winter the coldest it has ever gotten here is -8 c and -5c is regular in winter, no snow though. With protection from wind, rain, draughts and a high energy diet would the birds be able to tolerate this or would additional heating be necessary?

 

[Zoruace]

I dont think they would be able too
Anything under 40 degrees is too cold for a cockatiel

 

[StormyPica]

Agreed...

Even for a budgie, and the smaller birds get the more fragile they get.