My cousin and I have 10 chickens. They all started with sneezing and runny noses 2 weeks ago. We treated them with Tetroxy HCA for the last 14 days. 9 out of the 10 are all better. But we have one that is still sneezing. Can I still treat her with the tetroxy? Or should I do something else for her? Please help us out here.. We are both new to having chickens.