Why do all the ducklings/ young ducks all attack this one certain duck

Ducks do have a pecking order just like chickens- So its more than likely the younger ducks- being raised together are asserting their dominance over the call.  Being blind would also make this alot easier for them to achieve.

I had a similar thing happen here when I introduced some younger ducklings into a brooder containing a blind duck.  Although the older three- including the blind duck are now 5 weeks old- and the younger ones were 2 weeks old- One of the younger does pick on Steve- Ray quite alot.

I plan to have my duck in a small sectioned off part of the yard where food and water will always be in the same place. I will alternate companion ducks in the yard for her- as she does find food and water by listening to where the other ducks are.  How have you set things up for your call??  Have you found you had to do things a certain way to cater for her inability to see?

All birds will attack the one that does not appear normal.  Its a defense system that will protect the rest of the flock if a bird has a disease.  It a genetic trait and they all have it.  Blindness is not a disease to us, but the other birds don't know that.  All they know something is not right.  I had quails that at only 2 days of age attacked one in their flock.  I separated that one and sure enough something was wrong with it, because it died 2 days later.

It is a pecking order and it is the fact that the blind duck doesn't fight back. This leaves the door open for all the other ducks to prove they are higher in the order of things. Also, mother natures way of saying the duck is not normal. Poor little guy. I hope you find at least one duck that will befriend him. It would be nice if any animal would adopt him. I know my dog would.