Yesterday I took the quail's out of their cage to free range, and when picking up one of my hen's, I felt a mass on her back. Further inspection, I found a pretty large bump on her back near her tail-feathers. I'm not sure how big it is, but its definitely bigger than an average quail egg. It feels hard, but a little soft as well (probably because she's a little chubby). She's 2 years old and eating and drinking normally, however, sometimes she'll lie down and close her eyes for a bit before getting back up as if she were sick/tired. Her feathers stick out from where the bump is. Could it be a tumour? Infection? Any advice is greatly appreciated. Thanks in advance!