There's always a few dead fish floating around the lake in winter but this year there seems to be a bumper crop. This is due primarily to the cold and not disease or pollution according to the Missouri Department of Conservation. I've noticed a few extra shad locked in the ice myself and only hoping the crappie have faired well over the season.
2017 Update - The above post was in 2014 when the fish kill was due to an exceptionally cold winter. The March 2017 kill off, which affected catfish, walleye, and crappie has been attributed to a likely combination of bacteria, spawning and increased lake temperatures but is still under investigation. An additional kill of in May targeted paddlefish and is primarily attributed to the excessive water flow from Truman Dam during the flooding. Paddlefish were basically beaten to death flowing through the dam turbines.