I don't think I have an answer for you, but you should be concerned every time you have some sort of discharge. It is best to see a vet for further diagnosis. In the meanwhile I would give poultry vitamins and minerals. Especially the vitamin b group, because it effects the coordination and muscle movement capabilities. Ducks in particular need a lot of vitamin B3 also known as Niacin. You can also get Polyvisol Vitamins for infants without iron and give one drop 3 times per day directly into the bill. Niacin can be found in the adult vitamin isle and is mixed 100mg per 1 gallon. Be very careful with the chlamydia psitacci it is very contagious, even to humans.