Day olds do need a heat lamp, just like chickens. You can feed them chick starter, or you can get duck starter, but what ever you do chose make sure its NOT medicated. Ducks do not react well to all the medication in the feed. I would put some electrolytes in there water if you have it. And if you dont have any chick starter right there, make them some cooked and mashed potatoes, cooled of course. When they are old enough, if you choose to keep them, they get along with chickens just fine. At about a week or so of age I like to start giving my ducklings a daily bath, I find it helps build there leg muscle and teaches them how to groom at an early age.
Good luck!