"Tame" is a relative term when it comes to ducks. You may never get duck to eat out of your hand, it depends on the duck, but with time and patience, you can get them to come running when you show up with food and treats instead of running away. After a few weeks in their new home, they should be comfortable with it. Do they have an outdoor area they spend time in now? If not, I would watch them when they free range for a few weeks until they get use to the routine of going into the coop at night.