I have 3 Silkie chicks that hatched about 6 weeks ago. We've been putting them out in a private run during the day and bringing them in at night. I live in Vermont and it's getting into the 40's at night. When will they be able to be out all the time? We won't be introducing them to our flock of adult birds until they're full grown, but I would like to get them out of the house before winter. Thanks for any help! I've never had such tiny, delicate chickens before and I worry that they'll be too cold. They are fully feathered.