Thanks so much for all your answers! I did read the assisted hatching guide, but after the fact. I was just so worried about her temp. Also, I had just settled into a nice hot bath when my wife brought me the peeping egg, freaking out.
Btw, there was only a couple drops of blood, and no veins or streaking in the membrane. The blood seemed to be in one spot of the membrane. No sign of any yolk, it was all absorbed.
Goldie is a very good mom, but she allows only one human (me) near her babies or eggs, and that grudgingly. So I was still in the tub, hurrying to wash, when poor Becky tried to introduce the new baby to Goldie. Since Goldie had her 4-day-old with her, she got all freaked out at the human approach, likely 'cause it wasn't me. So, I will wait until tomorrow, as we are getting a cold front tonight and the low will be 50. I may let Goldie see the newborn tomorrow and let her hear the peeping, as the peeping seems to be the main cue for her mothering instincts. She has 4 youngsters from her last batch still here (out of 9!), and the day the peeping stopped, she drove them away from the food instead of calling them to it. Goldie still roosted with them, and otherwise acted like a flock mate, just not a solicitous mom. Shortly after, she began laying again.
Sorry for getting distracted...So, the plan is this: 1) keep baby warm tonight. 2) If still alive in AM, take it out to see mom for a few mins. 3) Put under mom tomorrow night if thing go well. 4) Don't go to sleep, check on baby several times to make sure mom hasn't evicted it from nest, etc. Sounds like a plan to me.
BTW, Goldie is the hen in my profile pic.