The vet should demonstrate how a bird is handled to be medicated properly without harming the bird. If you grip Cocoa a bit too hard you'll suffocate her as birds need their entire body to breathe properly. They don't have a diaphragm. There is a risk handling a bird already in respiratory distress but not treating properly is even more risky. Here's a good example of how it's done: https://www.youtube.com/watch?v=fUv7gFi8W3w
I want to see a positive change from antibiotic administration within the first half of the prescribed course. In other words, if I want to treat for 10 days, I want to see a positive change within the initial 5 days. If I don't, I need to consider another antibiotic; in this case, either doxycycline or trimethoprim/sulfa. Bacterial respiratory infections are most common in cockatiels. I need to also consider both fungal and viral infections as well as hypovitaminosis A (a lack of vitamin A in the diet) which can cause changes in the respiratory tract lining and symptoms similar to those of an infection. What has Cocoa's diet consisted of, please? Seeds should compose less than 20% of her diet. A diet of mainly seed and nuts has excessive fat, carbohydrates, and phosphorus; marginal protein; adequate vitamin E, and are deficient in amino acids, calcium, available phosphorus, sodium, manganese, zinc, iron, vitamins A, D3 (necessary for efficient absorption of calcium), K, and B12, riboflavin, pantothenic acid, choline, and available niacin. Ideally, a balanced pelleted diet such as can be found here: www.harrisonsbirdfoods.com or here: www.lafeber.com/pet-birds should be fed as well as hard boiled egg yolk, pancakes and cornbread, the tops of fresh greens, dairy products such as yogurt and cheese, fresh fruits such as apples, pears, melon, kiwi, and berries, vegetables such as broccoli, carrots, beets, asparagus, cabbage, sweet potato, and squash, and even tiny pieces of meat.