aeration will keep a hole open for the ducks but will not keep the entire pond clear of ice if there is extended cold weather. duck hunters use small agitating gadgets to ripple the surface in their hunting hole in order to keep ice from forming. maybe a few of these thrown out around the pond will help, just a suggestion. if a predator comes after one of your duckies, they would have another hole to take refuge. check Herters (a waterfowl hunting supplier)for the floating shakey gadgets. if you would like to discuss things a bit further, please send me an email (check my profile). I see your from MO, me too. I may be just up the road from ya.
