Hello! First I want to say, thank you all for this website and all your input! I have been getting help from this site since I started keeping birds a few years ago, so thank you! This is my first time posting and asking for help. I work at the feed store, and we had some ducklings that came in and no one was buying, so I bought them. One pekin, one buff, and one runner duck. They are about 5-6 weeks old. Everyone is eating and drinking (and POOPING—so much poop) normally, but the runner duck is not grooming and preening himself like the other 2 are. The other two finish eating and go to the big water dish and clear out their bills then rub water all over themselves and use their oil glands. They are nice and clean. But the runner duck just goes off and lays down next to the wall. I noticed today that he has crusty gunk on his face and his back and seems to have no interest in grooming. And I watch, the other two are not keeping him away from the water. There are two water dishes in the coop, so he does have access to water. I also bring down warm water so it’s not that he doesn’t want to groom in cold water (never had that stop a duck from grooming though) He also sometimes has these fits where his legs shake- almost vibrate- while he is standing, then he plops down. Not sure if the two are related. Any ideas? Thanks in advance!