Most good duck calls will reproduce the "feeding chuckle" "hail call" "laydown" and "quack" of a hen mallard. They won't reproduce the "raeb raeb" of a drake mallard. You can get by with an inexpensive plastic call like Haydel's DR-85 Double Reed Mallard. I guide and I've been using them for years. They make more expensive calls, but they have the same inner parts as the DR-85, they are just made out of more expensive material. Get a good calling tape from Haydel's and learn how to use your calls.
That being said, there is no "feeding call" that ducks use to get other ducks to come down and feed, The call referred to as a "feeding
chuckle" is actually the sound a hen mallard uses to get drake mallards to stay away from her, by telling them if they don't leave her alone her drake may attack them. But, the "feeding chuckle" does work, because it is what ducks often hear when they approach a bunch of hens and drakes.
The "hail call" is actually a hen mallard anouncing to the world that she is getting ready to "get engaged" in the fall, but the drake won't reap the benefits until next spring. Obviously any drake that doesn't already have a mate will respond to this "hail call" so that he can get engaged in the fall. I just had an article on this in the NRA American Hunter last year. Got more questions? Ask and I'll try to answer.

T.R. Michels

T.R. Michels