I have 4 khaki campbells ducklings that are 3 weeks old as of yesterday. One of them has this fascination with plucking the new feathers coming in on the other 3 and then eating them. It is plucking the whole quill part and all and since they are first coming in, there is some blood and loud peeping involved. They are in a 50 gallon trough and have plenty of room, plus we let them swim in the bathtub almost daily, but it is doing it to the others in there as well. I clean them out as often as possible, a minimum of twice daily, they are dry and happy otherwise. I am using the milk jug inside of another tub within the large trough they are in so it really minimizes the mess. They have a heat lamp yet for when they need it. Any ideas as to why the one is doing this? I have never had any problems like this with my chickens so I am at a loss as to what to do.
Goslings do that because they get bored and need to graze. You may want to try putting toys of some sort in there for them to chew on. If you can buy some crickets for the trough that may be your best bet since they're ducklings. Try to hand feed or leave some dying crickets in their food so they have a taste for them and aren't as terrified, then dump the rest in the pen. The bolder ones should try to chase after them. If not then any other birds you have will happily eat them. Good luck