Stress in broilers resulting from shackling

Area of Science:

• Animal Welfare Science
• Avian Physiology
• Stress Physiology

Background:

• Shackling is a common pre-slaughter procedure for broiler chickens.
• Understanding the physiological stress response to shackling is crucial for improving animal welfare.
• Previous research has not fully elucidated the dose-dependent effects of shackling duration on broiler stress.

Purpose of the Study:

• To investigate the impact of different shackling durations on the physiological stress response of broiler chickens.
• To determine the relationship between shackling time and key stress indicators.
• To establish an optimal shackling period to minimize stress in broilers.

Main Methods:

• Experiment conducted on 400 male Ross 308 broilers at 42 days of age.
• Three experimental groups: 30 seconds (T30), 60 seconds (T60), and 120 seconds (T120) of shackling.
• Measurements included plasma corticosterone, glucose, lactate, heterophil counts, heterophil:lymphocyte ratio, and tonic immobility duration.

Main Results:

• Elevated plasma corticosterone in T60 and T120 groups (P<0.05, P<0.01).
• Increased plasma glucose and lactate in T60 and T120 groups (P<0.05, P<0.01).
• Higher heterophil counts and heterophil:lymphocyte ratio in T120 group (P<0.01); increased tonic immobility in T60 and T120 groups (P<0.05).

Conclusions:

• Shackling is a significant stressor for broilers, with effects intensifying with duration.
• Stress indicators (corticosterone, glucose, lactate, heterophil:lymphocyte ratio) show positive correlation with shackling time.
• Optimal shackling duration should be maintained below 60 seconds to mitigate adverse stress responses in broiler chickens.