I have a 4 year old BO that has been having some breathing issues. For about a week she's been sneezing, shaking/scratching her head, and open mouth breathing on exhale. It seems worse at night on the roost bar or if I pick her up. I can hear rattling in her chest. She is still active throughout the day and seems to be eating well. I started her on Tetracycline a few days ago. I've been monitoring her crop size since she seems to be getting skinnier, and it's always on the smaller side. Tonight I noticed her crop seemed hard, and when i squished it around, feels gritty. I'm guessing that's grit in there and a lack of food. She seems like she has a good appetite but maybe she's not ingesting as much as it seems she is. Does anyone have any suggestions other than the Tetracycline I have her on?