Psychological and Physiological Stress in Hens With Bone Damage

Area of Science:

• Animal Behavior and Welfare
• Bone Biology
• Stress Physiology

Background:

• Abnormal bone development impacts physical and psychological health in animals.
• Limited research exists on the specific psychosocial factors influencing poor bone conditions.
• Laying hens are a suitable model for studying bone health and stress responses.

Purpose of the Study:

• To investigate the association between psychosocial factors (fear, social behavior) and bone condition in laying hens.
• To determine if pre-laying behavioral traits predict bone health during the laying period.
• To explore the relationship between bone damage, stress markers, and behavioral reactivity.

Main Methods:

• Behavioral tests including open-field, aerial predator, and social reinstatement tests were conducted on 93 low-productive laying hens.
• Bone condition was assessed via palpation, with induced damage in some hens.
• Feather corticosterone (CORT) concentration and body weight were measured at various ages.

Main Results:

• No significant association was found between pre-laying fear, CORT levels, body weight, and bone damage at 29 weeks.
• During the laying period, bone damage correlated with increased pecking, reduced open-field activity, and improved sociality.
• Psychological stress, indicated by fear behavior, was elevated in hens with poor bone condition, but physiological stress (feather CORT) was not.

Conclusions:

• Bone health in laying hens is interconnected with fear-related behaviors and social interactions.
• Psychological stress, rather than physiological stress markers like feather CORT, appears linked to compromised bone condition.
• This research offers novel insights into the complex interplay between bone health and behavioral responses in animals.