Research comparing conventional litter and alternative perforated flooring (netting) systems is relatively limited under commercial production conditions. A comprehensive comparison of broiler production performances, welfare quality, and housing environment of two broiler houses with conventional litter and new perforated plastic floors was conducted over four flocks for eight months in eastern China. The two broiler houses each had 31,700 broilers per flock on average and were ventilated using a negative-pressure system. Prior to the onset of the monitoring, litter/manure in all houses was removed. The environmental conditions, gaseous concentrations, and ventilation rate were recorded continuously. Production performance and welfare quality data were collected weekly. Results showed that indoor temperature and relative humidity were not affected by the different floors when the two houses had the same ventilation configuration and management. The average ammonia concentration was lower at 10.44 ppm in the litter house compared to 15.02 ppm in the netting flooring house due to the manure accumulation under the floor. Broiler production performance including live weight, feed conversion, and mortality, was not affected by the netting floor compared to the litter system. In addition, the results suggested that birds raised in the netting floor house may increase breast blister incidence. In this study, the welfare quality parameters including hock and foot pad lesions, lameness, and fearfulness levels were similar in both for both flooring systems.