Dusty, you may want to try putting some structure in the deeper water for them to hide untill the water turkeys are gone and then pull it out. If you have cloudy water the turkeys will be more likely to leave you alone. My water is cloudier than it was a few years ago and I haven't seen a single bird this year.
Another thing I've noticed, is that the stomach contents of a few that I "found dead" were full of fatheads (the pink kind) instead of my catfish. Brightly colored, slow, and soft as opposed to dark, slow and spiney? It would be an easy choice for me. And fatheads would be a beneficial addition to your pond.

And if you feed your fish pretty good they will be too big for them next winter.