My 6 month old black austrolorp has been exhibiting what I can best describe as labored exhalation for the past few days. She has also been sneezing intermittently. When I pick her up, she doesn't appear to be in any pain. Just this unusual bellowing sound. She is scratching, pecking, eating and drinking normally, although yesterday when I gave the flock (4 girls) yogurt for the first time she appeared to eat the most, making me think that she was hungry and not eating her normal pellets due to obstruction or sore throat. There is no foul smell when I look in her mouth, and no discharge from eyes or beak. Crop/vent appears normal. She has not started to lay yet. None of the other girls have any symptoms, and none of them have been wormed (all droppings appear normal). I am at a loss for what to do as I know these things can go downhill quickly, and I would like to be proactive and avoid a vet visit. Could this be respiratory disease or worms of some sort? If so, what medication would I use? Thanks in advance.