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

Abstract

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.

Injury and mortality in broilers during handling and transport to slaughter

“…Jones et al (1998) found that when broilers were inverted and shackled, the frequency and duration of struggling increased with increasing light intensity. Although one recent study found evidence that loading during the night compared with during the day, increased the risk of bruising in the wings and breasts (Jacobs et al 2017b), this is in contrast to previous work that showed a slight reduction in the % of bruising in birds loaded in the dark compared with those loaded during daylight hours (Taylor and Helbacka 1968).…”

“…Jespensen (1982) identified that the procedures at one processing plant prior to shackling could involve a crate of birds dropping 2 m, potentially resulting in injury to the breast and back of the birds. Jacobs et al (2017b) did not identify any birds with leg fractures, but recorded an increase in the % of broilers with wing fractures from 0.12 % before loading, to 1.88 % after, either manual or mechanical catching and loading into modules. After transport and lairage, there was no significant increase in the % of birds with wing fractures.…”

“…It is likely that the manner in which birds are carried and handled differs between catching teams. In Belgium, Jacobs et al (2017b) reported differences between catching teams in the % of birds with bruised wings or breasts.…”

Slaughter of animals: poultry

“…In Italy, Grilli et al. () estimated this time for 233 different batches of broilers as ranging between 0.2 and 9.4 h with a mean of 4 h. A Belgian study (Jacobs et al., ) undertaken in six slaughter plants, found lairage durations from 15 to 555 min (9.3 h), with a mean at 275 min (4 h 35 min) for broiler chickens. Lairage for 3–4 h in a controlled lairage environment during the summer and spring is considered as necessary to reduce the thermal load of broiler chickens (Vieira et al., 2011a).…”

Risk factors for bruising and mortality of broilers during manual handling, module loading, transport, and lairage

“…Catching and carrying a broiler inverted by its legs can cause wing flapping and struggling (Newberry and Blair 1993) and sometimes injury and death (Gregory and Austin 1992;Nijdam et al 2006). Variation between the manner in which different catching teams handle the birds can affect DOA % (Nijdam et al 2004) and the percentage of birds with bruising (Taylor and Helbacka 1968;Langkabel et al 2015;Jacobs et al 2017). Bruising is a superficial injury that occurs after trauma (Hamdy et al 1961).…”