She could have a respiratory disease or worms that affect her throat and breathing. Gapeworm or capillary worms could do that. If it is a respiratory disease, it could be a virus or a fungal one that won't respond to antibiotics. That is not a cough or sneeze, but gaping and stridor, from something in her airway, such as mucus plugs, worms, or something else. I would take her to a vet if possible, but look into her throat with a flashlight while someone holds her, to see if there is something blocking her throat. Then I would worm her with SafeGuard liquid goat wormer 1/4 ml per pound, given 5 days in a row, which would treat both gapeworm or capillary worms. A vet could do a fecal float to look for those worms as well. If it were a virus such as infectious bronchitis or ILT, then it would have to runit's course over several weeks. ILT typically causes blood-tinged mucus from the beak, while IB usually causes sneezing.