Chick clicking when breathing?

[Theck1722]

Pick up the other babies and hold next to your ear. It is very common to hear such a noise in a perfectly healthy baby chick. If they all mostly sound like that, you're probably ok.

I know this post is so old but it’s the only one that’s given me some hope.
My 6 week old chicks making a crackle/popping sound but I can only hear it when I put my ear right up to them. I’ve heard it for weeks but nobody has gotten sick. All active, eating and drinking. I’m hyper aware with these chicks.. painfully so. Possibly normal?