Leonie Jacobs

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

&NA; 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.

Effect of post-hatch transportation duration and parental age on broiler chicken quality, welfare, and productivity

Broiler chicks are transported to production sites within one to 2 d post-hatch. Possible effects of this transportation are poorly understood and could vary among chicks from breeder flocks of different ages. The aim of the present study was to investigate the effects of transportation duration and parental flock age on chick welfare, productivity, and quality. After hatch in a commercial hatchery, 1,620 mixed-sex chicks from 29-wk old (young) and 1,620 chicks from 60-wk old (old) breeders were subjected to transportation of 1.5 h or 11 h duration. After transportation, 2,800 chicks were divided among 100 pens, with each pen containing 28 chicks from one transportation crate (2 or 3 pens per crate). From the remaining chicks, on average 6 chicks (min 4, max 8) per crate (n = 228) were randomly selected and assessed for chick quality, weighed, and culled for yolk sac weighing (one d). Chicks that had not been assigned to pens or were not used for post-transportation measurements, were removed from the experiment (n = 212). Mortality, ADG, BW, and feed conversion (FC) of the experimental chicks were recorded until 41 d. Meat quality was measured for breast fillets (n = 47). No interaction effect of parental age and transportation duration was found for any variables. BW and yolk sac weight at one d were lower for chicks transported 11 h than 1.5 h and for chicks from young versus old breeders. The effect of parental flock age on BW persisted until slaughter. Additionally, parental age positively affected ADG until slaughter. Chick quality was lower in chicks from old versus young breeders. Chick quality and productivity were not affected by transportation duration. Mortality and meat quality were not affected by either parental age or transportation duration. To conclude, no long-term detrimental effects were found from long post-hatch transportation in chicks from young or old parent flocks. Based on these results, we suggest that 11 h post-hatch transportations under similar conditions do not impose long-term welfare or productivity risks.

Impact of the separate pre-slaughter stages on broiler chicken welfare

&NA; Before broilers are slaughtered, several parties are involved in catching, loading, transportation and lairage. During these pre‐slaughter activities, broilers are exposed to a variety of stressors. A detailed understanding of how broiler welfare is impaired during each stage could help the responsible parties to make targeted improvements. The aim of this study was to identify welfare problems occurring during the consecutive stages of commercial broiler transportation and to identify risk factors associated with the identified welfare problems. Commercial Belgian transports (n = 81) were assessed in spring (n = 14), summer (n = 33), autumn (n = 10), and winter (n = 24), and potential risk factors were recorded by the observer. Animal‐based welfare indicators were scored before the start of the pre‐slaughter phase as well as after the catching, transport and lairage, and slaughter stages to assess the impact of each stage. The most frequently observed welfare impairments were vent and thigh lesions, panting, wing fractures, and bruising on wings and breasts. Our results show that the impact of the pre‐slaughter phase on broiler welfare is multifaceted. The overall pre‐slaughter phase resulted in a mean weight decrease of 5.3%, a prevalence of 1.4% in leg bruising, and 3.7% in breast or wing bruising. Wing fractures occurred mainly during the catching stage: Prevalence increased from 0.1% to 1.9% (P = 0.003). A welfare comparison before and after transportation and lairage revealed that plumage had become more soiled (P = 0.003), body temperature decreased by 0.7°C (P < 0.001), huddling prevalence increased by 0.5% (P = 0.008), prevalence of birds with splayed legs increased by 0.08% (P = 0.008), prevalence of supine birds decreased by 0.05% (P = 0.003), and 0.1% fewer birds with wings stuck in the crates (P = 0.010) were observed. Risk factor analyses revealed that carefully choosing the catching crew, minimizing thermal stress, reducing duration of transportation, and worker training are promising actions that may improve broiler welfare during the pre‐slaughter phase.

Impact of transportation duration on stress responses in day-old chicks from young and old breeders

The aim of this study was to assess the interaction effect of transportation duration and parental age on physiological stress responses and quality in day-old chicks. After hatch, 3240 chicks from either 29-week old (young) or 60-week old (old) broiler breeders were transported for 1.5h (short) or 11h (long). Thereafter, 228 chicks were assessed for quality and blood plasma was assayed for corticosterone (CORT), lactate, glucose, and thiobarbituric acid-reactive substances (TBARS, increased concentrations can indicate oxidative stress). No interaction effects of parental age and transportation duration were found (all P>0.10). Chicks from young breeders showed higher CORT levels (P=0.007) and were of higher quality (Tona method, P<0.001) than those from old breeders. After long transportation, chicks showed increased CORT (P<0.001) and lower TBARS levels (P<0.001) compared to after short transportation. No evidence was provided that long transportation differently affected the quality or stress responses of chicks from breeder flocks of two ages.