Is this a normal chick sound/behavior?

[Amuuya]

Hi, I’m raising chicks for the first time and I’m a little confused. This is the third day I’ve had them. The first day they were all peeping really loudly until they settled in as expected, and two of them have visibly grown. (At least I think they have, I could be imagining it. Or maybe they’re just standing taller because they’ve settled in?) Yesterday the smallest one starting making this noise and started pestering the other two even when they were sleeping. It had a pasty butt that has now been corrected, but is this normal behavior? The other two aren’t doing it. They were a little bigger than the other when I picked them up, but it really looks different now.
I couldn’t get the YouTube link to embed, sorry. https://youtube.com/shorts/7_8hCFz6F0Q?feature=share

 

[Thunder344]

Bump.

 

[TheCrochetChick]

I had one that did this and it just got worse and worse. I finally had to give her away because she ripped open my silkies bum. She was a lavender orpington. i only had 2 ladies and just found out that my other one is a male so now I have none and am so bummed.

 

[Crazy Maizie]

They sound fine. I would just watch the pestering to be sure it doesn't get out of hand.