Fluid looking pouch

[Clt1988]

I just bought 3 tolbunt polish chicks and the 2 frizzles have a fluid looking pouch on side of wing/neck area. Is this normal? Should I be concerned?

TIA

 

[Clt1988]

Just to add they seem happy and active. They are 4 weeks old.

 

[nuthatched]

Is it their crop?

 

[Clt1988]

Is it their crop?

From what I'm researching I'm thinking maybe? I never noticed it I'm my other chicks.