Today we found baby mallard ducks in are pool...there are 4 NEED ANSWERS A.S.AP?

we found four baby ducks in our pool today,we look everywhere for the mother and she wasnt around so we put them in a box with some corn with water in the corn to make it soft and then we put some water in there for them, there about two inches what should we do? and we dont want to let them go cause we dont want them to die.