So we got two ducks from TractorSupply about 4 weeks ago.. They have been inside in large dog pin about 3ftx2ft. In the past week they have started loosing there feathers, at first i thought it was because they were about to lose the chick down and start to get feathers but now I am not so sure. When I got home today their back is mostly bald! We don't see any mites on them. What else could make them go bald?