How to Manage These?

We have 5 baby chicks and 5 full grown chickens and one duck. The duck keeps getting injured by something in the coop. The birds are obviously pecking at its eye, the baby chicks have since the day we brought them home together, but in the big coop now that they're bigger they seem to get along much better. The adult chickens keep to one side of the coop and the babies and the duckling (we've had him a month, he's huge now) all stay on the opposite side. They snuggle together and seem fine. I separated the duck from everyone today because of his eye injury that was fresh this morning, but he is upset and wants back in the coop with the others. The baby chicks changed sides and sit by the side of the coop that he is on and the other adult birds are upset that the duck is free and they are not. They've been trying to dig their way out all day. Should I separate all the babies from the adults and see what happens? Or separate all the chickens from the duck in the same coop? Right now all the chickens are in the coop and the duck is roaming around our fenced in garden area that the coop is in. So they are basically still kinda together but separated by the coop walls. Help. I hate seeing the duck get hurt but I don't necessarily want him to be upset all day either. He quacks and squeaks and doesn't really eat much and won't get in his pool outside the coop away from his buddies.

maybe get him a little duck friend?

He had one and the chickens killed it on sat or sun

Maybe get another duck and pen them separately from the chickens. Or, find someone else who has ducks and give him to them. Obviously it's not working to keep the chickens and ducks together.

I would agree, get another duck or two and house them separately from the chickens.