I have been dealing with what I thought was a niacin deficiency in a 3 week old toulouse gosling for the last week. His (I'm not actually sure if its the male or female) feet were curled up last week, so he was either walking on his knees (I guess?) or 'swimming' along the ground. I had been treating him with fortified vitamin b complex, but stopped that the last few days, and have been giving him baths to try to strengthen his muscles. I also hobbled his legs because they looked like they were going directions they were not meant to go. He seems to be making some marginal improvement and today I braced his feet with cardboard to try to keep them straight. I went to put him back after his bath and physical therapy, and I noticed that several of my 2 week old meat birds (25 rangers and 25 'pioneer' chickens) look like they are starting to do the same thing. They are all on a 20% meat bird grower from a local feed mill. None of the other waterfowl are having issues, and my 25 assorted male chicks are all fine as well. The goose was in a raised brooder with a well supported hardware cloth floor, but is now in with the meat birds, which is concrete with shavings and straw for bedding. Any idea what could be going on? The only thought I have is something with the feed?