Indians used to put a dead fish under their corn plants for fertilizer, or so I've read. This is probably some eco-freak who's been picking it up to keep the roads clean and thereby depriving the coyotes and magpies of their groceries. Oregon has all kinds. I'll be the neighbors downwind will be more than glad when it's gone.
Plenty around here drop a carp into a hole a couple of months before planting vegetables, I drilled a hole in the back yard and filled it with roo guts last year in preparation for planting a fruit salad tree later this year.