2Appleby M C,Smith S F,Hughes B O. Nesting,dust bathing and perching by laying hens in cages-effects of design on behaviour and welfare[J]. British Poultry Science, 1993,34(5) :835-947.
3Appleby M C. The Edinburgh modified cage:effects of group size and space allowance on brown laying hens [J]. Journal of Applied Poultry Research, 1998,7(2) : 152-161.
4Appleby M C,Walker A W,Nicol C J,et al. Development of furnished cages for laying hem [J]. Poultry Science,2002,43 (4) :489-500.
5Hughes B O,Appleby M C. Increase in bone strength of spent laying hens housed in modified cages with perches [J]. The Veterinary Record, 1989,124(18) : 483-484.
6Voslarova E,Hanzalek Z,Vecerek V,et al. Comparison between laying hen performance in the cage system and the deep litter system on a diet free from animal protein [J]. Acta Veterinaria Brno, 2006,75 (2) : 219-225.
7Castellini C,Perella F,Mugnai C,et al. Welfare,productivity and qualitative traits of egg in laying hens reared under different rearing systems [C]. XII European Poultry Conference,2006,10- 14.
9Weitzenburger D,Vits A,Hamann H,et al.Effect of furnished small group housing systems and furnished cages on mortality and causes of death in two layer strains [J]. British Poultry Science, 2005,46(5):553-559.
10Hurmik J F. Animal welfare:ethical aspects and practical considerations[Jl. Poultry Science,1990,69:1827-1834.
9Appleby M C, Hughes B O, Elson H A. Behaviour, Management and Welfare. In.. Poultry Production Systems. Wallingford: CAB International, 1992:207.
10Appleby M C, Hughes B O. Welfare of laying hens in cages and alternative systems: Environmental, physical and behavioural aspects. Worlds Poultry Science, 1991, 47: 109-128.
