Truffles is gone. She fought a good fight... she hung in there longer than I thought she could. She went to sleep with her sisters, and grew stiff by next water time. Sisters were still snuggled up to her, not trampling her, just snuggled up, sharing their warmth with her... but she was no longer there. When I picked her up, she was stiff as a stone covered with fluff.
I thank you all for your help and advice. At least we have a proper heating set up now unlike any we've had before, for the rest of the chicks. The other 9 chicks all appear quite healthy, apart from the next smallest one who has a pasty butt... my husband has cleaned her off, and we're using olive oil to try to prevent it again, but she's as active as the others, so we aren't really worried about her. Just keeping an eye on that.
Thank you so much again for all your help!
Katie Sue