Strange noise from back-end of chick/pullet.

So i picked up a new Splash polish chick/pullet earlier today, I'm guessing she's 6 weeks old, I'd be glad to post pictures, if you'd like to see her.
She's making this faint and strange, grinding, crackling noise. It seems to be coming from her back end, not her breathing or from her head at all. It almost sounds like two feathers grinding together, but she is NOT moving. Nothing is moving that I can see. At all. She's sitting on my hand and I can hear it- I thought it ment she was about to poop, but from what I can tell she's only pooped twice since I got her around 1 today. Her vent is totally clear.
She was in an outdoor run near many other larger chickens and some quail and a turkey and some piglets.
Now she is, and will be until she's big enough to join the other girls, in pine only shavings I buy from Tractor Supply.
I think she had been on medicated crumbles but will be on organic feed and scraps from now on.
She's acting as normal as an uprooted chick can act, and is snuggled up in a towel in my lap right now.

I'm just wondering if this is digestion noises or is worms moving around or is something else I should be worried about. I got a chick from the same place two weeks ago and got it home and realized it was a Roo and returned it- He made these noises a little too, but my first round of chicks didn't make these at all that I remember.

Any thoughts from the more experienced?
 

Pictures coming shortly then! She's just adorable!
It's not really a purr. and it's defiantly coming from her vent area- if I poke around the soft spot below her vent I can get it to happen.
Maybe I can pick it up on a video.
I inspected all of the poop in the tub she's been in, and nothing had worms in it- I don't know if they wormed her or not- and i don't know who the poos are from since I dropped off a brother and picked her up and they were both from the same farm.

So I got a video of the noise. It's loud enough if I have her in my lap I can hear her.

First off- here's a slightly fuzzy but super sassy picture of her.


The noise you hear at the beginning is it, and it happens again at the very end. sorry it's shakey and crazy but it's more about the audio.
I'm guessing this is a crested splash polish or some variation, but she kept calling it a rockstar sebright. which isn't right at all, but nothing that teenager told me has turned out to be right so I'm ok with that.
It happens every 20-30 seconds or so.
Is she underfed and I can just hear her stomach growling?
Again, she's acting pretty normal.
 

I've gotten two poos in the last 30 minutes. No worms. Tight and White, like Ashley English taught me!

Y'all.


Seriously??

How adorable is this little lady!