Broiler chickens dead on arrival: associated risk factors and welfare indicators

Abstract

The pre-slaughter phase of the production process has potentially important animal welfare implications, including mortality (recorded as "Dead on Arrivals"; DOA: ). To reduce DOA%, specific risk factors need to be identified. DOA% can also be used as a first and quick screening of pre-slaughter broiler welfare under commercial conditions. The aim of the present study was to identify risk factors for DOA% in commercial broiler flocks and to find associations between DOA% and animal-based indicators of broiler welfare during the pre-slaughter phase. Eighty-one transported flocks to five slaughter plants were assessed. Farmers provided information on the flock and observers gathered data on pre-slaughter factors. DOA% was recorded by slaughter plant personnel. The association between risk factors and DOA% was tested using linear mixed models, with slaughter plant as the random effect. Mean (± SE) DOA% was 0.30 ± 0.05% and median was 0.19% (range 0.04 to 3.34%). Two risk factors for DOA% were identified, both related to flock health status during the production phase. Higher DOA% was found when farmers did not check chick quality upon arrival (P = 0.011), although one extreme DOA% caused this significant effect. In addition, on-farm mortality during production (including selective culling) was negatively associated with DOA% (P = 0.011), potentially due to the selective culling on farm. Further research is needed on the impact of on-farm health status on welfare during the pre-slaughter phase, as the current study provided some evidence that on-farm factors are linked to mortality during the pre-slaughter phase. No specific characteristics of the pre-slaughter phase could be identified as risk factor for increased mortality. DOA% was positively associated with five welfare indicators, including indicators of thermal stress, which indicates the potential to use DOA% as a quick, cost-efficient screening tool for those welfare aspects.

Injury and mortality in broilers during handling and transport to slaughter

“…This is compatible with reports from various studies conducted in Europe since 1990, where most studies have reported a % DOA of broilers transported to slaughter of 0.2% with a range from 0.1 to 0.6% (Bayliss and Hinton 1990; Warriss et al 1992;Gregory and Austin 1992;Hunter et al 2001;Nijdam et al 2004;Warriss et al 2005;Petracci et al 2006;Haslam et al 2008;Chauvin et al 2011;Jacobs et al 2017a). There are many variables that can affect the risk of injury and mortality.…”

“…Jacobs et al (2017a) reported a significant association between the % of broilers observed to be lying on their back after placement into modules and the % DOA. In containers with a lid and in those that require a drawer to slide into a module, there is a risk of birds getting trapped and injured.…”

“…In the United Kingdom, Haslam et al (2008) reported a significant correlation between mortality during rearing and % DOA and in a study in France; Chauvin et al (2011) found a significant influence of mortality during the rearing period on % DOA. Jacobs et al (2017a) found that when rigorous culling to remove unfit birds during rearing was included in the % mortality during rearing; there was a negative relationship with % DOA. If producers cull sick and disabled birds during rearing (Ansong-Danquah 1987) and catchers identify birds that are either not fit for transport or are too small for slaughter, there are fewer birds at risk of mortality during transport due to pre-existing conditions.…”

Comparison of flock characteristics, journey duration and pathology between flocks with a normal and a high percentage of broilers ‘dead-on-arrival’ at abattoirs

“…Mortality during the journey is 53 a recognized problem, both due to animal welfare issues, but also due to the 54 considerable economic losses resulting from the large number of animals involved 55 (Ritz et al, 2005). Although the term welfare is relevant only when an animal is alive, 56 mortality during the journey is likely preceded by a period of poor welfare and the 57 percentage of broilers dead on arrival (DOA) can possibly be used as a quick 58 indication of pre-slaughter welfare (Jacobs et al, 2016). to death (Mitchell and Kettlewell, 1998).…”

Slaughter of animals: poultry

“…The preslaughter phase has potentially important animal welfare implications (Medina‐Vara et al., ), which are usually measured by dead on arrival (DoA) at the slaughterhouse (Jacobs et al., ; for details, see Section 3.7.2). In Canada, Caffrey et al.…”