You could try to put her in a cardboard box with her nestmate and that feather duster. That would give her company and may help her detach from you, and attach to her brother/sister.
A little bit of forced bonding. Remember she is really young.
I have incubated all of my chickens all of my life, until recently.
I bought 2 little silkies and one of them went broody for me, and she hatched out 4 little babies (barnyard mutt chickens).
The difference in hatching these 2 ways is crazy. The ones that mom hatches were much more 'wild' then the incubated ones, and you can tell they are very attached to mom. If I try to pick one up, then the chick becomes obsessed about getting back to mom. It doesn't appear that its out of fear, it seems more like instinct.
That baby you have, was it incubated, or hatched under a broody mom. If it were hatched under a broody mom, then I understand. That's why I recommended the small box, to make it socialize.