Well, we have PIP and the beginnings of ZIP!
Nettie, I buy them a high protein game feed for now, but wont be able to totally do my experiment until Spring. I have a pond to dig, and I am going to try and use duck weed to help clear the water as well as feed it back to the ducks. You can make duckweed up to 50% of their feed without health issues, but I think I will keep it less than that.
Along with there commercial feed, they are free ranging in the yard and have already earned their keep by eliminating several patches of noxious weeds. I have seen them diving after bugs in the last few days too. It is finally getting nice here and the bugs are hatching. When the cats are picky and leave half of their grain-free salmon wet cat food to go stale, the ducks are happy to take care of that for them.
They also get a "salad" every morning floated on their water. Their favorite is the tips and ends of bok choy. They also like nappa cabbage, leaf lettuce scraps, peas and green beans (I had a bag of french cut beans that got freezer burned. I was going to throw them out but decided to see if the ducks would like them...they did!).
I tried to find sources for meal worms, but dammnnn they are expensive. I don't know if I can get past the ICK factor to grow my own. I may do red worms though. Worms don't bother me and I am working on a compost pile anyway.