They will like the pond.... AND the predators will thank you for the food!
It's not Disneyland out there. I know the sight of wild Mallards in a pond is very exciting, but there is a big potential for a lot of deaths. If you want them as pets, don't do it. If you just want to see Mallards on the pond, then take your chances.
Mallards will migrate, so be prepared for some taking to the air and possibly not returning. Feeding them certainly is a big benefit, but again, no guarantees they will "stay".
Good Luck!