We've had the rubber stall mats in the horses and donkey stalls and all along the aisle. My chickens and ducks (when I had ducks) were around them daily while they were free ranging and they ate things they would find off the mats in the aisle that were not covered in bedding (ie. picking through horse and donkey nuggets) and they were fine. The barn has open stalls on the top so the horses could all see each other and there was plenty of airflow so the birds weren't enclosed with the fumes though.