I have a male Pekin that is about 4 or 5 years old. He had a very bad limp a few weeks ago. I confined him for ten days and he seemed to do better. Unfortunately he seems very lethargic now although he is eating a drinking. He spends a lot of time sleeping by himself but does join others in the pond once during the day. He is still a bit gimpy but not like he was previously. I couldn't find any wounds on him. Any ideas?