Could be someone is chewing on the lil one. They will do things like that if they don't have alot of room to move around but they also do loose some down as new feathers begin to appear. Looks like they are in a pool? so it must not be from lack of space. That is just the cutest pic of that leg around the neck. You might want to sit and watch to see if you can catch anyone chewing on the lil one. I would also remove the news paper too slick and can cause leg problems. Pee pads or [rubber shelf liner which can be washed and reused] is good ideas. Do you get to take them outside for some exercise? or is it too cold now.
The one buff duck with the leg around it's neck....it is losing all its "feathers" around its head. Doesn't look like it has a sore or anything. It started out like a wet spot on its head (I thought it was just wet down sticking to her head) but it is spreading to both sides of the face and head. Any idea? Is it just losing down to prepare for short hair/feathers or ????