I have 4 white chinese geese that are about 3 months old. As best as I can tell at this age, there are 2 males and 2 females. For the past month, one of my females has been having muscle spasms in her neck. The rest of her body doesn't vibrate like her neck does. I'm not overly concerned at this point because she seems to be completely healthy, but I haven't seen anything like it. She only does it when she comes up to me looking for "goodies" or the rest of them are wound up and trying to intimidate me, but of course it would be difficult for me to see this at a distance. Has anyone else ever seen this?