Did you see my post about running low watt pet heating pads plugged into small, portable invertors run off rechargeable power tool batteries? Maybe you could rig up something similar near her?A hen might die trying to hatch. If she becomes hypothermic she won't move - that's the warmest spot nearby, then can't. I do hope she hatches safely and is no worse for the wear, but I am very worried for her with these temps!