Not knowing if it’s genetic, why wouldn’t you keep them?? If you hatch a few eggs from them and the offspring have the same issue, then you’d know. But without confirmation... ? :idunno
:hugs they are better off with you, so look at it as you rescued them!
By the way, you mentioned that you remove the water at night. I assume you also remove the feedd?? Ducklings should always have access to water if they have access to food. Just making sure.... :)
I would think outside time would be good for them, especially if it's warm outside. Some bathing/swimming water would be good too. Maybe they are rubbing their natural oil gland but not getting it spread properly? :hu
Interesting. I haven't seen anything like it either. Could we see more pics? Very curious.
What type of bedding do you use? Maybe an allergic reaction to something?