There was a tip in this month' s Field and Stream (I think) that talked about setting decoys in bunches. Their idea was to take a cast net or some other netting material and attach the decoys to it with about a foot of decoy cord. This would allow the net to sink out of sight and the decoys could still move with the wind.

The tip claimed you could just roll it up, decoys and all, and carry it wherever you went hunting. Sounds to me that in the dark or a real windy day, it could become a big tangle.