Do they have small shelters? If they can keep out of the wind and are dry, they should be able to handle the cold easily. During the coldest times I will feed mine some mealworms to keep their fat layer up, but not a huge amount.Yep
Would a higher protein be better in colder temps though? I know it’s almost spring now, but I’ve lost two birds just during this cold snap, and a few more over the winter. I remember that I lost quite a few birds this time last year as well