I was always under the belief that turkeys go to open fields in rain storms due to their extreme hearing. The sounds of the rain hitting the leaves, etc...in the woods makes it very difficult for them to hear the sounds of predators. Being in a field in a down pour they still hear alot of extra noise with the rain, but now they have a safety buffer zone in the field that they can now rely on their eyes to make up for their handicap in hearing.
It is nearly fool proof, when a good rain comes, go to an open field or an open clearing in the woods and you will find turkeys.
