Found Ritual Site? Voodoo?

We found an animal cage hanging in a tree near a lake. Tied to the top cage wires was a white handsewn bag tied in a way that left it dangling in the middle/inside the wire cage. Thinking it was some sort of trap or injured animal, we removed the cage and opened the bag. Inside the bag were feathers, two chicken feet, a knife, a seashell and a severed rat's head. There were other things weird about the site but to start....does anyone know what it is we stumbled upon?