Table 4. Results of multivariable analysis (ranked by p-value).

Variable	Odds Ratio (CI 95%)	p-value
Age of hens		< 0.01
till 40 weeks	ref	ref
40–60 weeks	5.41 (2. 02–14.53)	< 0.01
older than 60 weeks	2.28 (0.94–5.53)	0.07
Use of bedding material	4.22 (1.40–12.75)	0.01
Horses present	2.67 (1.16–6.12)	0.02

For the multivariable analysis 139 farms were selected, 12 had missing values for one or more of the selected variables.