I'm not worried. Momma will take care of them. I had a Nankin bantam hen hatch out bantam chicks in the middle of February one year and they did fine. If I see there are issues, I'll take them in the house for the winter. I'll get pictures once she brings them out.Congrats on your hatch. I hope they do well--have you hatched this late in the season before? Any concerns about winter weather and babies? Oh, and we need pictures!