Gasping & Vomiting really stinky clear fluid

[katharbour]

Found one of our hens tonight gasping and vomiting clear stinky fluid. Any thoughts?

 

[ChickNanny13]

Crop issues?
Have you checked her crop, is it squishy or hard?
Is it empty in the morning?
Full at night?
Eating/drinking/pooping ok?
Age?
Laying? When last laid?

 

[LA Farmer]

Possible sour crop.