I did this with a bat I found once. I covered the cadaver with a few smaller rocks and one big one, tucked behind a hydrangea in the garden, out of the way of, well, everyone. I went back a year later, and the rocks were undisturbed, but there was no skeleton. Weird bats are.
it probably wasn’t dead or resurrected or something :/
But seriously, I have tried the same thing with mice and birds the cat catches and if you leave them to long the bones breakdown to. In a bucket of water for small things works well and you know all the ‘parts’ will be in there somewhere!