I recently bought a Khaki Campbell duck at a flea market. I was told by the seller that you can keep her in the same run and coop as your chickens. I put the duck in a cage and put her in the chicken run. (To let the chickens get a feel of her). Later that evening I decide to take her out of the cage, (with me in there in case something went wrong), and one of my chickens attacked her and the other 5 joined right in. Including my barred rock rooster who was the last one to join in. How can I get the chickens used to my new duck?