Multi-factorial investigation of various housing systems for laying hens

Abstract

1. The advantages and disadvantages of various housing systems for laying hens were compared as a pilot study for work in commercial conditions.

2. At 16 weeks of age, 284 hens were introduced into one of 6 housing systems: two types of conventional cages (small: SC; large: LC), furnished cages (small: SF; large: LF), and non-cage systems (single-tiered aviary: SA; free-range: FR).

3. We evaluated the welfare, egg production, and immune response of the birds in these housing systems, built in the same location, for 18 months. For welfare evaluation, we examined their ethology, physiology, anatomy, production, and physical condition.

4. The non-cage systems, especially FR, had a low score for freedom from pain, injury, and disease, together with other disadvantages, such as pale eggs and increased feed intake for production. However, the score for freedom to express normal behaviour was high and immune response was good in the non-cage systems.

5. In the furnished cages, behaviour was more diverse in SF than in LF, and in SF immune response was comparable with the non-cage systems.

6. For freedom from fear and distress, the non-cage systems had high scores for some indicators such as TI duration, H/L ratio and claw length, while aggressive pecking and feather pecking was worse in the housing systems with large group sizes.

Acknowledgements

This research was supported in part by a Grant-in-Aid for JSPS Fellows (no. 19-11909) and for Scientific Research C (no. 19580318) from the Japanese Society for the Promotion of Science. We are grateful to Professor T. Suganuma, T. Kondo, and E. Takizawa for measurement of bone permeability, to Dr H. Wall for technical assistance in the TI test, and to the staff of Kanagawa Prefectural Livestock Industry Technical Center for technical assistance and help. The English language was revised by Catherine Ono.