Ventilation Rate, Air Circulation, and Bird Disturbance: Effects on the Incidence of Cellulitis and Broiler Performance

Abstract

Environmental quality is believed to play an important role in the growth rate and carcass quality of broiler chickens. The effects of ventilation rate, air circulation (air speed at bird height), and bird disturbance on broiler performance and carcass traits were measured in two trials from 6 to 41 d. The two levels of ventilation were 1.7 and 3.4 L/s per bird (3.6 and 7.2 cfm/bird); the two levels of air speed were 0.32 and 0.82 m/s (63 and 161 ft/min); and the lower and higher levels of bird disturbance occurred by manually feeding and automatically feeding the birds, respectively. Birds in both trials were individually weighed on d 41 and processed on d 42. The ambient temperature ranged from 35°C on d 1 to 20°C on d 40. During the last week, even though the setpoint was near 20°C, the maximum daily temperature occasionally approached 30°C. The higher airspeed treatment (0.82m/s) resulted in a significantly higher production rate per unit floor area than the lower airspeed treatment. The birds in the higher airspeed treatment were 30 g (0.066 lb) heavier than those in the lower airspeed treatment. A significant interaction between ventilation rate and air speed showed that broilers in the higher ventilation/lower airspeed treatment consumed less water than any other treatment. The effects of ventilation rate, airspeed, and disturbance on feed consumption, water consumption, feed conversion ratio, and water to feed ratio were not significant. Birds exposed to the lower ventilation treatment consumed more water than birds in the higher ventilation treatment. Neither broiler mortality nor incidence of cellulitis was affected by ventilation rate, air speed, or disturbance level. Treatment differences in breast muscle weights were not significant. It was concluded higher yield per unit area with good carcass quality could be achieved when ventilation rate and air circulation were adequate.