3-4 wk old chick - possibly impacted crop?

[jollygreen23]

My first chicks are probably 3-4 weeks old. One of them is drooling and I'm worried about her. Is this an impacted crop? Her crop felt pretty full, but I don't know if maybe she just ate a lot. I put ACV in their water, so naturally, there's a sour smell to her drool.
I gave her some water, massaged her crop, and turned her upside down to try and empty the crop, but I don't think I got everything out.
She's been eating chick crumbles and sometimes I put tufts of grass (with dirt, roots, etc) in there for them to work on.

 

[jollygreen23]

I don't know what to do! No labored breathing. She's acting pretty normal, but her crop is huge! Please help.