Space and density effects on group size preferences in laying hens

Area of Science:

• Animal behavior
• Ethology
• Animal welfare science

Background:

• Understanding space and group size preferences is crucial for optimizing housing conditions for laying hens.
• Previous research has indicated varying preferences, necessitating further investigation into the interplay of these factors.

Purpose of the Study:

• To investigate the preferences of laying hens for different group sizes and spatial volumes in deep litter systems.
• To determine if individual hen characteristics, such as dominance status, influence these preferences.

Main Methods:

• T-maze preference tests were employed to assess choices between different group size and space configurations.
• Experiment 1 compared preferences between a large group/large space and a small group/small space, and then with constant large space.
• Experiment 2 tested preferences for various group size/space options, using aggressive (peckers) and subordinate (receivers) hens.

Main Results:

• Hens showed a preference for larger spaces and smaller group sizes when space was constant.
• Preferences included a larger group (70 vs. 4 or 0 hens) and a larger space (9 m2 vs. 1 m2).
• Subordinate hens (receivers) were more consistent in their preferences than aggressive hens (peckers).

Conclusions:

• Optimal housing for laying hens requires a balance between smaller group sizes and adequate spatial volume.
• Individual dominance status may influence the ideal group size, highlighting the need for tailored management strategies.
• These findings have significant implications for improving the welfare of laying hens in commercial and research settings.