How's it going? Any sign of the little one? I agree with wvduckchick - check inside mama's feathers. I have a friend who kept taking chicks out of their mama's feathers, until I think, he counted 8 or 9 - and it was almost impossible to tell they were in there, she just looked 'winter puffed out." I prayed!
So, you may have gathered, I'm not much of a broody expert, but if they're like any chickens I know, they really hate change, so moving the nest might actually cause more harm than letting mama try to keep them warm outside (chickens are like little ovens - have you ever slid a hand up under their wing while they're sitting in a nesting box? Nice and toasty!)