Occurrence of Salmonella spp.: a comparison between indoor and outdoor housing of broilers and laying hens

Table 1 Flocks of laying hens tested positive for Salmonella in indoor and outdoor production in Sweden

Year	Housing capacity^a		No. test-positive flocks		No. birds in test-positive flocks		No. birds in test-positive flocks/total housing capacity (%)
Year	Indoor	Outdoor	Indoor	Outdoor	Indoor	Outdoor	Indoor	Outdoor
2007	5,649,000	351,000	1	2	Nd^b	Nd^b	Nd^b	Nd^b
2008	5,285,639	413,305	5	0	66,900	0	1.3	0.0
2009	5,457,711	646,930	1	2	20,000	2820	0.4	0.4
2010	5,690,353	708,435	2	0	23,600	0	0.4	0.0
2011	5,922,995	769,939	0	0	0	0	0.0	0.0
2012	6,222,224	816,864	2	0	17,600	0	0.3	0.0
2013	6,312,001	875,437	7	0	69,800	0	1.1	0.0
2014	6,217,685	896,371	1	1	6600	18,000	0.1	2.0
215	6,289,060	1,153,615	2	0	39,399	0	0.6	0.0
Total^c 2008–2015	47,397,668	6,280,895	20	3	243,899	20,820	0.5	0.3

^aMaximum total number of laying hens at one time in laying hen houses
^bNot available
^cYear 2007 not included since data on number of birds in test-positive flocks was missing