Also, do you know the gender of your ducks? Keeping a drake with chickens is very risky. He can seriously injure or kill the hens while attempting to mate them.
Unfortunately, he is a CX (Cornish Cross), a meat breed meant to grow very large very fast. This is the age that you would be butchering him. It would be kindest to him if you could find someone to process him for you. They often have leg issues and problems with their internal organs, leading...