Why are my ducks loosening feathers

It is likely that they are molting. Ducks (and other birds, such as chickens) molt throughout summer and fall. They lose their feathers, and grow them back over a period of around six weeks.

Another possibility is that your ducks are being pecked. Other ducks or birds may be pulling out the feathers. Some reasons for picking are not enough space, overcrowding, and insufficient feed or water. To stop picking, isolate the offending birds, or spray BlueKote onto the bare areas.

I hope this helps!