My budgie is about 4, lives completely outside of the cage, and has been entirely healthy. As the title says, the budgie still holds his wings in an X shape, but one wing is noticeably lower than the other. He is also not as active as before and flies around less. I suspect that it's from him recently hitting a door, but the injury doesn't seem bad enough for him to stop flying. Is there anything I should worry about or do, or is it going to pass on its own? I attached pictures of him with the wing.