Theirs two parts to an imprint. The actual imprint upon hatching (The first animal it sees bigger than itself). And the bonding (Who handles the animal the most, spends the most time with it)
The hen hatches them, they will imprint on chickens. The ducks will assume they are chickens, and depnding on the bonding, they might try to be near the chickens. If it bonds with the Hen, they will follow her around and love her until they are grown. Again they still might try to be near the chickens and probably won't be as friendly or nice to humans. If you take them away from the hen at hatching and raise them in a brooder where you can spend tons of time with them, they will be more likely to like humans and may be friendlier to you, but they will always think they are chickens.
A duckling that is hatched in an incubator usually sees humans first and thinks it's a human. If several ducklings are raised in a brooder and handled a lot by humans, they usually will like humans and go near them when they are older. While these ducks are usually a lot nicer/friendlier, they can have issues with following the wrong humans if they get out (like up to a street or someone that might harm them), esp since they think they are humans.
Any duckling that is hatched in a incubator, and raised alone very closely with humans will not only assume it humans, but they tend to want to be treated like one as well (ahem, my ducks, lol). These ducks don't do well living outside where they can't be near humans most of the time. MY ducks live inside my house and get upset with me if i am gone longer than a few hours. I don't reccommend this type of imprinting for any beginner or anyone who wants to retain their sanity.
