Trilling sound from a 2 week old chick

[MamaBelle5]

She's part EE and part amberlink. She's making this odd trilling sound and I'm not sure if it's just her chirp or if it is something else. Please let me know if the video comes through okay. They're not too cold, may be too hot, but I don't think so, you can't see it but they can get further away from the heat, they're all kind of hanging out in the middle between the warmer and colder sections.

Thank you!

 

[Luckylarson]

Mine do that often. Sometimes they are telling another chick to get off them, but most of the time it seems like an experiment to see how much noise they can make! We have lots of chicks in different brooders and sometimes when one makes this noise all the others go quite. Maybe they are trying to talk to the chicks in the other brooders that they can't see?