At first I figured she must have died of something else and then gotten picked at by birds because you should have some predator prints in that mud! But then I thought, what if she got into the ditch and stayed there awhile, to get away from dogs or wolves? Then after they left her, she was to chilled and stressed to survive. In that case there should be prints in the mud around the ditch where she crossed. If you can't find prints, she died of something else.