I have a 3 week old duckling that all of a sudden can't peep. He tries but nothing comes out but a very weak raspy peep. Yesterday it almost felt like something was in his lung. Like water. I could feel a squeaky noise when I held him when he tried to peep. Today he tries to peep and nothing comes out. Other than that he appears to be fine, eats, drinks and acts normal. What could be wrong with him and what can I do to help him? Thank you.