How to get the smell out of a piano - a bird decomposed behind it...?

So, I have a piano in my bedroom and it's pretty new - only 4 or 5 years old. My room started to smell really bad and I hunted everywhere but couldn't find anything. Finally, I checked behind my piano and a dead and decomposing bird was down there. My cat must have dropped it down. It must have been there for about a month. It got vacuumed up and wiped away, but still stank. Then I wiped it down with a mix of bleach and water and it still reeks and I can't get rid of it. Any ideas on what is safe to use on a piano but will get rid of them smell? It's horrendous. Thanks!