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Rearing Enrichments Affected Ranging Behavior in Free-Range Laying Hens
Dana L M Campbell1, Tim R Dyall1, Jeff A Downing2
1Agriculture and Food, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Armidale, NSW, Australia.
Frontiers in Veterinary Science
|September 14, 2020
Summary
Rearing Hy-Line Brown® pullets with structural enrichments increased their ranging behavior in free-range systems. Novelty enrichments reduced range visits, while both groups showed longer outdoor durations, indicating varied impacts of enrichment on hen welfare.
Area of Science:
- Animal Science
- Ethology
- Poultry Production
Background:
- Free-range poultry systems are common in Australia, but pullets are typically reared indoors, creating a potential mismatch with layer housing.
- This housing discrepancy may impede pullet adaptation to free-range environments, highlighting the need for effective rearing strategies.
- Rearing enrichments are proposed as a method to enhance pullet development and improve adaptation to diverse housing conditions.
Purpose of the Study:
- To investigate the impact of different rearing enrichments on the ranging behavior of pullets in a free-range system.
- To assess how novelty and structural enrichments during the indoor rearing phase influence subsequent outdoor activity and stress responses.
Main Methods:
- 1,386 Hy-Line Brown® chicks were reared for 16 weeks under three conditions: standard floor-housing (control), weekly novel objects (novelty), and custom H-shaped structures (structural).
- Pullets were transitioned to an experimental free-range system, and their daily ranging behavior was tracked using radio-frequency identification (RFID) technology from 25 to 64 weeks.
- Video analysis quantified range use, and albumen corticosterone concentrations were measured before and after initial range access to assess stress.
Main Results:
- Structural hens exhibited the most extensive ranging behavior across most age periods, while novelty hens showed the fewest range visits.
- Both enriched groups demonstrated longer maximum visit durations to the range compared to controls, indicating increased engagement with the outdoor environment.
- While all hens initially adapted slowly to range use, structural hens displayed higher albumen corticosterone levels pre-access, which equalized post-access across all groups.
Conclusions:
- Different rearing enrichments significantly influence pullet ranging behavior in free-range systems, with structural enrichments promoting greater outdoor activity.
- The study suggests that enrichment type plays a crucial role in shaping adaptation to free-range environments, impacting both behavior and physiological stress.
- Further research into the underlying mechanisms, potentially involving brain lateralization, is recommended to fully understand these enrichment effects.
