Table 5.

Multivariable linear mixed models related to performance and health parameters in 2309 flocks from 358 broiler farms in 7 EU member states

Model	Dependent variable	Independent variablea	p-value	B-value
1	Overall mortality rate	Mortality rate after 7 days	< 0.001	1.03
		Floor qualityb	< 0.001	- 0.72
		Neonatal septicemia	< 0.001	0.22
2	First week mortality rate	Floor quality	0.004	- 0.67
		Ventilation typec	< 0.001	0.72
		No other professional activities by farmer	< 0.001	0.24
		Neonatal septicemiad	0.014	- 0.12
3	Mortality rate after seven days	Floor quality	0.046	- 0.35
4	Dead on arrival	Light management during catchinge	0.003	0.09
		Type of drinking system	< 0.001	- 0.41
		Daily growth (g/d)	< 0.001	0.01
5	Condemnation rate	Type of drinking system	0.001	- 1.40
		Daily growth (g/d)	< 0.001	0.05
		Feed withdrawal time	< 0.001	- 0.12
		Number of birds in the broilerhouse	0.002	0.02
		Presence of recirculation vents	0.039	0.25
		Septicemia after seven days	0.012	0.23
		Type of feed	< 0.001	0.75
		Ventilation typec,f	0.057	- 0.31
6	Feed conversion rate	Daily growth (g/d)	< 0.001	- 0.01
		Light intensity adaptations	0.013	0.02
		Ventilation typec	0.001	- 0.03
		Necrotic enteritis problems	0.014	- 0.02
		Daily check of drink water flow	0.002	- 0.03
7	Daily growth	Feed conversion rate	< 0.001	- 29.35
		Coccidiosis problems	0.004	1.33
8	European production index	Sex of day old chicksg	<  0.001	34.54
		Dysbacteriosis problems	0.002	14.97
		Evaluation of daily registered results	< 0.001	- 33.94
		Daily inspection of feed and water system	0.029	- 12.80
		Type of drinking systemh	0.006	54.37
		Type of feedi	0.024	- 13.01

^aOnly the statistically significant risk factors in the final models are presented; ^bThe reference used for floor quality was a floor in perfect conditions without cracks; ^cThe reference used for type of ventilation was roof ventilation; ^dThis was only the case in tunnel-ventilated broiler houses; ^eThe reference for light adaptation was dimming the light intensity; ^fInterpreted as a trend, as it was not significant (p > 0.05); ^gIf only male chicks were housed, a higher EPI was present; ^hThe reference used for drinking system was the nipple drinking system; ⁱOnly the case when dysbacteriosis was absent in the flock