When a goat chokes they wil cough up foam...once they have it loosened up they are fine...what are her labor symtoms..do you have a due date on her? You said ligs are gone, bag is full..is it tight and strudded? babies dropped ? restless??
could be early stages...they will stretch and move around to get babies set up right...with the choking and foam Im thinking she may have upset her rumen, goats in heavy labor will twist their jaw like a funny yawn..but rarely grind thier teeth...gut pain will cause teeth grinding....I would give her C D Antitoxin and a baking soda drench...1/2-1 teaspon baking soda in enough water to drench and a good dose of probios to kick start her flora...offer fresh water and hay tonight, no feed just yet...if her rumen is off the grain will be hard to digest..