Hello! So 9 days ago I got my two budgies. The pet shop I got them from offered me a free vet consultation, so the next day I went to the vet and she told me that they are healthy (just that my female budgie is missing her tail, but it's nothing to worry about, cause its going to grow back). A few days ago, I noticed that my female budgie's tail is bobbing up and down quite noticeable (you can see a video of her here) , so I googled it, and I'm worried that she might be sick? I've read that their tails bob when they have respiratory problems, but the vet didn't tell me anything. She doesn't seem sick apart from the tail bobbing, she's eating a lot and chirping and playing. What should I do?