Georgia Newbie with new concern...

Hello all.
I'm new to this website, sort of. I've been visiting it for about a year now, but this is my first time joining. Last February I starting buying books on chickens, and in April I brought home eight wonderful little chicks. I have a slight concern, however, that my chicken books and magazines dont seem to answer. My girls did not moult this past fall. We've had an uncommonly warm winter, and for the past few weeks the nights have gotten very cold. For whatever reason, two of my girls seem to be moulting now. I just want to be certain they'll be warm enough while the new feathers are developing. Also, I can't seem to find any information on dietary changes during moulting or winter seasons. Any help is greatly appreciated. My girls are doing wonderfully, I just wanted to voice these concerns in time, should this be a problem for them.

-Saralyn