Wast bad. The one that had chickens in it might be a challenge.

Rub some dirt, and a few consistently churned boxes of baking soda on it.

I had blood at the bottom of my cooler. Smelled horrible

The plastic absorbs the smell. You won't get it out.

Try letting coffee grounds sit in it for awhile. Replace them frequently to keep them fresh. The idea is to.soak the coffee smell into the plastic so it's stronger than the dead things smell.