My observations on the photo based on all the roadkills I’ve salvaged are.
There is no blood on the trailer on the deck behind the elk so I doubt it was a roadkill.
Everyone I’ve have picked up and drove down a side logging road and gutted then drug back on the truck had a bloody slide mark and hair stuck to the bed of the truck and tailgate. Unless they had a crane to lift it on and off, but there still would be blood running out of the chest cavity and down the boards.When I zoom in it almost looks like the chest cavity blood is dark like it was hung open for a couple days.
It almost looks as if predators ate on it and it is a few days old maybe.