Bantam Cochin - Strange noise

[Wokawidget]

Hi, I have had a bantam cochin since she was 2 weeks old. She's now 12 weeks.
Over the last few months I have heard many noises from her, and I think I have almost mastered 90% of what they mean...50% of the time

The noises she makes are:

Cheepity-cheep-cheep-cheep : I want something
CHEEPITY-CHEEP-CHEEP-CHEEP: I am sat on your lap...now stroke me!
PUUUURRRRR : I like being stroked
CHEEEP!-Cluck-cluck : Is that a cat or an eagle?...no wait, it was a baby sparrow.
Cheep-cheep : This looks interesting
Cheep-cheep-cheep-cheep-cheep-cheep: Oy! other chickens let me snuggle up to you I am small and cold

plus various other small noises depending on what interesting things she's found in the garden.
In the last few weeks she has started throwing in an interesting grating sound. It sounds a bit like when you put a blade of grass between your fingers and blow. For the purpose of this post, I will refer to this noise as Kzzzt.

So, her call for wanting something sometimes sounds like: Cheepity-cheep-cheep-Kzzzzzzzzt
She doesn't always do it, and she throws the Kzzzzzzzt sound in randomly with any noise she makes. Not often, but sometimes, she just makes the Kzzzzzzt noise on it's own.

Would this be her voice "breaking"? Does Kzzzzt turn into a cluck cluck?

Cheers,

Woka