I had a lone chick hatch today (my first hatch ever). I have two 3 1/2 week old chicks, and opted to put the new baby in once she was dry. I moved the cuckoo maran chick to a small hen house with a heat light (she's enclosed) nd kept our silkie chick with the newborn. pluggie, the silkie, is kinda special and so far they seem to be getting along splendidly. I was farid the CM would tromple the baby.
Anyway, Pluggie the silkie baby acts more like a newborn. She's all cuddled up with new Wynona. She's about 1 1/2 times the new peep's size, and was behind in growth from her hatching mates (who I adopted out). She kept getting "poop plugs'' stuck to her butt (hence "Pluggie") in her first week or so, which I had to manually remove, cusing a bald butt. I suspect she's literally a dwarf or something, beyond being bantam.
I like the idea of a partition if you can, or keeping her separate with a mirror & comfort item, unless your other chicks are small.
Let us know how it goes...