|
Numbers and percentage of commercial laying hen flocks submitted for necropsy to SVA and included in the study. |
||||||||
| 2001 |
2002 |
2003 |
2004 |
|||||
|
|
||||||||
| Housing systems |
N |
% |
N |
% |
N |
% |
N |
% |
|
|
||||||||
| Cages1 |
5 |
41.7 |
6 |
9.1 |
4 |
9.5 |
5 |
9.6 |
| Litter-based systems2 |
5 |
41.7 |
54 |
81.8 |
32 |
76.2 |
38 |
73.1 |
| Free range3 |
2 |
16.6 |
6 |
9.1 |
6 |
14.3 |
9 |
17.3 |
|
|
||||||||
| Total |
12 |
100 |
66 |
100 |
42 |
100 |
52 |
100 |
|
1Includes conventional battery cages and enriched cages. 2Includes single-tiered floor systems and multi-tiered aviary systems. 3Flocks housed in litter-based systems indoors, with access to outdoor pens and pasture, including organic flocks. | ||||||||
Fossum et al. Acta Veterinaria Scandinavica 2009 51:3 doi:10.1186/1751-0147-51-3 |
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