Plz help! Ques about cleaning bunnies cages!?

My bunnies live outside. They liv in a hut about 2 to 3 feet off the ground. When they poop The poop falls to the ground(they have a chicken wire bottom to thier cage) When i clean up the poop from the ground there is a terrible oder. Is there anything i can put on it to make it have less oder? I dont want to put harmful chemicals cause my bunnies will be breathing it in any ideas??? Thanks!!