This has happened to 3 young geese. 3 different years. During mid-summer. One recovered somewhat , has some issues with gait , but otherwise healthy. One I put down and did an autopsy on and didn't see anything abnormal,organs all looked healthy This year another young gandar 'has it'. They start having difficulty walking, will flip over sometimes, and rest a lot, they still have an appetite and try to swim and preen. (they have some pools, not dug ponds or lakes.)....Ruled out genetics. All I can come up with is something like West Nile virus, or mild botulism, or some kind of toxin. I do not use sprays on my property anywhere the fowl have access. I only mound treat fire ants. I have a variety of grasses, weeds, trees and a few holly...this is rural farmland area in the South....supplemented feed is grains (corn, wheat, millet and poultry layer). They are a rare breed and it is rather heartbreaking....anyone have a clue?