First, I don't know if waddling has a specific definition in the poultry world. So, if you are misled by the title, I'm sorry. The patient is a 4 week old Ameracana chick. Yesterday she started to waddle around on her tail. She almost always moves like that now. She has her tail end down, almost on the floor, and she scuttles along on her lower legs. If I push her legs forward and set her down on them, she will walk normally for a little, until she trips or sits down. Sometimes she will return to normal by herself. I have studied her legs and joints carefully; there seems to be no resistance or little to flexing and straightening. There is no swelling anywhere. I can't find any problem. Occasionally I would hear a little click or pop as I examined her, but they seemed to make no difference. She's running around actively with her flock when she's normal; chasing other chicks with toys, being chased by them, etc. All help is appreciated.