Thanks so much to everyone who responded. I'm going to either purchase a heat lamp (with a dimmer) for her enclosure to warm it up a bit or move her to a warmer area in the house as a first step, since I am a bit worried about her temps at night when I can't monitor it, and it is getting colder. I'm also going to take the advice of EL-Ziggy and make sure the pinky is nice and warm before offering it. If that doesn't work, I'll give Daniel's deli cup idea a shot. I'll keep this thread updated with my progress as we go along here.

And, just for reference, my MBK is currently weighing in at 30 grams (although this was my first time weighing her since I brought her home... yikes). I'll be keeping a very close eye on that as well as time goes on.