Move out the larger pieces of furniture. Once, I was vacuuming and found a dead bird.
The only solution, in that case, is to actually open up the wall so you can get access. You are bumming. Take a very, very sharp razor knife and cut a hole about 8"x8" between the studs, and if you have to cut old lathes, so be it. Get a small saw. What you want to do is get the nozzle of a shop vac down into the space.
I have a dead cat under my house
Really? I thought it just smelled like updog..
Have you been eating BEANS ?
Now I have to find where she sit sat shat
Does it smell mouse-sized, bird-sized, or bigger?
I've never known a cat to kill a bat. You sir need to sleep with one eye open.