Our Muscovy drake can't use his legs, he moves by waddling back and forth on his feet, dragging himself on the ground. It is sad and pathetic to watch him try to move, he mostly just sits. In all other regards he seems healthy, though obviously distressed. He has gotten very heavy and it appears his rather small legs simply can't lift his body, but how did he get so heavy? Should we put him on a 'diet'? Is there a nutritional deficiency that has affected the strength of his legs? Have had several drakes over the years and never seen this before, and he is neither young nor old, just sort of middle-age for a Muscovy so surprised this has developed. We've separated him from the two very active ducks he lives with to see if more rest and managing is food might help. Any suggestions appreciated.