Checking Trailer Floor Boards
Although nothing replaces having your trailer's soundness regularly evaluated by a professional, to give a preliminary check to your older trailer's floorboards, try the old cowboy ice pick trick. To start, take an ice pick and ram it into the floorboards in key areas, such as where your horse stands and where he urinates. If the wood is still sturdy, the ice pick will stand strong like a tree. If the floorboards are starting to rot you'll be able to "wobble" the ice pick back and forth and side to side. Test the floor boards from the top and bottom.
Article is printer here with permission from Horseillustrated.com