When my Perdy passed away, we brought her to the vet and they disposed of the body. Maybe you can look into that?? It didn't cost us anything either, I don't think, since we didn't have her cremated.

EDIT: Another thing I just thought of, see if you can find a metal box to put her body in?? Then bury that. That way if it gets dug up whatever it is can't get inside.

OR cover the area with a bunch of large stones.

OR bury her a few feet deep, AND with a bunch of stones covering the site.