Hi
Your Khaki Campbells will adjust to eating out of the food dish you provide. Ducks are extremely messy so keeping food in a container is a must as they will toss some out on their own as they eat. An adjustment time period is normal. I like to keep both food and water outside of the coop in their run. The inside is for shelter and laying purposes only, this makes the coop easier to keep clean also. Their food and water dishes are on opposite sides of the run because ducks will get a mouthful of food and dunk right into the water, or vice versa. If you are able to find out what brand food they had before you could mix the 2 and slowly wean them into the food you provide solely. Try providing some pieces of greens, lettuce, cabbage etc. They will get used to you and their new environment.
Best wishes!
I was wondering about that. Food on one side and water on the other, so they have to walk from one to the other?