When my silkie had her chicks, she kept them inside for 2 days then off she went to the pen and the little ones were running and playing, then they would all get under mom and take a nap and get warm. I was surprised at the amount of time they were out in the cold. But they always had nice warm mom nearby.
Chickens have survived for thousands of years without our help.
Just be aware of what can be on the ground... fertilizers, pesticides, the like.
Is mama hatching them, or did you order from a hatchery?