Influence of sudden changes in management program on physiological and behavioral parameters in hens

The present study was designed to test the effects of sudden changes of food access and light duration on the physiological and behavioral parameters of hens. The physiological parameters investigated were heart rate (HR), body temperature (BT), and locomotor activity (LA) using a radiotelemetry system. After implantation of the telemetry transmitters, six hens were housed individually in cages under constant environmental conditions for 10 days with a photoperiod of 15 h light (04.00–19.00 hours), and food was available ad libitum at all times. After that, the same hens were subjected to a feed withdrawal trial, from 12.00 to 08.30 hours, followed by a lighting hour reduction trial by changing the time of lights‐off from 19.00 to 14.00 hours. The physiological and behavioral data were recorded for 2 days before each trial, as control data. With the feed withdrawal trial, during the light and dark periods, HR and BT were significantly lower in the hens without food access than in the control. Whereas, LA was significantly lower only during the light period in the hens without food access than in the control. Further, the time spent resting increased significantly, but the time spent feeding decreased significantly in the hens without food access than in the control. Also, the number of times the cage was pecked and pecking of the feeder occured at a significantly higher level, while the number of times beaks were wiped occured at a significantly lower level in the hens without food access than in the control. With the lighting hour reduction trial, during the light period, HR and BT were significantly higher, whereas LA was significantly lower in the ’sudden light‐off’ treated hens than in the control. In addition, during the dark period, HR, BT and LA were significantly higher in the sudden light‐off treated hens than in the control. Moreover, in the sudden light‐off treated hens, the time spent preening and feeding decreased significantly, but the time spent resting increased significantly than in the control. It is concluded that sudden changes in a management program might result in many significant differences as were found in the physiological and behavioral parameters of hens in the present study.