Laying hens are kept in a range of housing systems but there have been few studies that have collected comprehensive, valid, un-confounded data to compare hen welfare across these systems.

A total of 26 flocks representing conventional cages (6 CC), furnished cages (6 FC), barn (7 B) and free-range (7 FR) systems were studied and data collected in three ways.

Each flock was visited three times throughout the laying period and detailed data collected on the history, housing, husbandry, climate, health and welfare of the hens.

The producers were asked to complete and return a weekly questionnaire on welfare and husbandry. At the end of lay, 150 hens from each flock underwent post-mortem examination.

Indicators assessed by the researchers that were significantly (repeated measures ANOVA) influenced by housing system included:

• gentle feather pecks (CC=0.01; FC=0.06; B=0.16; FR=0.38 pecks/hen/minute),
• mean percentage of hens with feather damage (FR=15.0; CC=24.7; FC=24.9; B=26.9) and
• faecal corticosterone (FC=11.2; CC=14.3; FR=16.1; B=21.6 ng/g).

Post mortem analysis revealed that housing system significantly influenced levels of the following variables (assessed on ordinal scales of 0 (least damage) to 3 (most damage)):

• skin damage (CC=0.59; FC=1.05; B=1.31; FR=1.68) and
• keel protrusion (CC=0.91; FC=1.00; B=1.12; FR=1.21).

The percentage of birds with old keel fractures also varied with housing system (CC=17.7; FC=31.7; FR=59.8; B=69.1) as did the percentage with keel fractures incurred at depopulation (B=1.2; FR=1.33; FC=3.63; CC=24.6) and the percentage of hens that were vent pecked (FC=1.6; CC=6.2; B=10.0; FR=22.5).

Weekly questionnaires from the producers revealed significant effects of housing system on the percentage of eggs with blood on (FC=0.83; CC=0.98; FR=1.42; B=2.05), and eggs with calcification spots (FC=1.2; FR=1.7; CC=3.5; B=4.1).

This study did not include a detailed analysis of all hen behaviours but, considering the indicators of physical well-being and stress response that were measured, the welfare of hens in the FC system appeared to be better than that of hens in other systems, concluded Professor Nicol.

Reference

Nicol, C.J., S.N. Brown, S.M. Haslam, B. Hothersall, L. Melotti, G.J. Richards and C.M. Sherwin. 2009. The welfare of laying hens in four different housing systems in the UK. Proceedings of 8th Poultry Welfare Symposium, Cervia, Italy, 18-22 May 2009, p12.

The symposium abstract was dedicated to the memory of Dr Sue Haslam.

Further Reading

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You can see other papers presented at the 8th European Symposium on Poultry Welfare by clicking here.