i wonder if lightly poached eggs & olive oil would help...
the vet sites say the trachea is normally coated with phlegm, so i'm wondering if an oil/protein supplement might not help..
the eggs are cheap, & super high quality.. the yolks have cholesterol, which although is fine for younger dogs (assuming she can eat eggs), you might want to reconsider, if she's older..
also, i'd avoid straight dry food.. make sure she's hydrated..
if it gets worse, check the vet sites for antibiotics that can be used, & compare that against what you can buy at tractor suppy or other farm stores..
do the dosage calculations very carefully..
sorry she's ill, man..