Baby chick is acting different

[Sevenbantams]

Today one of my babies started making a weird noise and just opens and closes beak. Can anyone help me find out what ot could be.

 

[DobieLover]

How old is the chick?
How many do you have in the brooder?
What are you feeding them?
Can you get a video of her making the noise, upload it to YouTube or another online video platform and post a link here?