Clingy chick- normal behavior? Slightly concerned...

I've got my 4 new chicks in a brooder in the house because we wanted to get them really comfortable with people. We've been holding them all multiple times daily (just for 20-30 seconds or so). Last night I held one of my Orpingtons for quite awhile, which was a first-- the Orps are much more amenable to being held, and this one seemed pretty content to just sleep in my hand.

This morning she woke me up cheeping at 5:30. Everything seemed to be fine so I went back to bed. I got up at 7 and she was still going, so I wondered if she'd gotten spoiled by excess holding and wanted more. I picked her up and put her on my shoulder, where she burrowed into my bathrobe collar and went to sleep. I've been putting her back periodically because I'm busy and it's hard for her to stay warm and comfortable enough with my moving around, but each time I put her back she'll hang out for half an hour or so with the others before starting up her cheeping again. I can tell hers from the others now. She seems healthy enough and other than being mellower than the others, seems to eat similarly and bed down with them just fine.

So is this just a super social chick? Or is this a sick behavior (kind of like kids)? I wouldn't mind it much if I knew it wasn't something to be concerned about. We have one other orp who is pretty okay with being held, but she hasn't acted like this. But she has yet to be held for a long period, either, so I have no idea if she'd pick up the same trait if I were to introduce her to the concept.

Thoughts? Thanks!