We currently have no rooster, and therefor decided to let one of our hens, who goes broody every month or so, hatch a fertile duck egg. Everything went well, and she successfully hatched a little Pekin duckling. He is 4 weeks old now, growing well, and seems active and lively, but he only walks a few steps at time, and then plops down on his haunches (reminds me of one of those poor broiler hens, who can only walk a few steps, because their unnaturally large breast weighs them down so much). We feed our duckling unmedicated starter chickfeed, and he free-ranges with the flock during the day, and sleeps in a secure pen at night (under his chicken mom). Any ideas?