My grandmothers cockatiel seems to have a lump hung from his back end. She told us yesterday and so I’ve come today to have a look but have no idea what it could be. The bird is 22 years old and is eating/drinking normally. I’ve spoken to our local vet who is calling me back (but may not be today 🙄) so I am looking for any explanation as to what it could be as the last thing I was is him suffering. Any help would be greatly appreciated. I have attached a picture for reference.