This study investigated the protective effects of an on-farm management package designed to reduce injurious pecking (IP) in loose-housed laying hens. A systematic review of scientific literature generated 46 potentially protective management strategies. Bespoke management packages were designed for treatment flocks (TF) using these management strategies. IP in 53 TFs was compared with IP in 47 control flocks (CF) where the management package was not employed. Scoring of plumage damage (PD) and observations of gentle and severe feather pecking (GFP; SFP), and vent and cannibalistic pecking (VP) were completed, and management strategy use was recorded, at 20, 30 and 40 weeks of age. Differences between treatment and CF were examined using multilevel modelling. Compared with CF, TF employed more management strategies (P<0.001), had lower PD (P=0.003) and SFP (P=0.019). Regardless of treatment or control flock status, the more of the 46 management strategies that were employed the lower was the PD (P=0.004), GFP (P=0.021), SFP (P=0.043), mortality at 40 weeks (P=0.025), and the likelihood of VP (P=0.021). Therefore, the provision of a bespoke management package was protective against the majority of forms of IP in commercial laying hen flocks.
Editorial Introduction With millions of affected animals worldwide, ungulates are the most prevalent mammalian stereotypers. Agricultural ungulate stereotypies were also the first to attract serious scientific study. They therefore dominated the first edition of this book, and it seems probable that more individuals with stereotypies have now been studied in this taxon than in any other. Examples of the behaviours that Bergeron and co-authors consider here include crib-biting by horses, sham-chewing by sows and tongue-rolling by cattle and giraffes. Concerns about animal welfare and economic issues (e.g. stock value or productivity) have meant that many studies aimed to reduce these behaviours, rather than understand the niceties of their underlying mechanisms. Nevertheless, motivational explanations for ungulates' oral stereotypic behaviours have been developed, and to some extent tested. Ungulates are primarily herbivorous, and much evidence supports the hypotheses that their oral stereotypic behaviours derive from natural foraging. The forms of the movements are often similar, with some abnormal behaviours even involving ingestion (e.g. wood-chewing by horses); they typically peak with the delivery of food or end of a meal; and, like natural foraging, they are often reduced by factors increasing satiety. Thus, in practice, replacing captive ungulates' typically lowfibre, high-concentrate provisions with more naturalistic foodstuffs successfully reduces oral abnormal behaviour across a wide range of species. But what exactly is the link between natural foraging and oral stereotypic behaviour? This is less certain, and Bergeron and her colleagues review three principal hypotheses. The first is that captive ungulates' diets do not fully satisfy them, because they give too little gut fill, are deficient in specific ways (e.g. too low in salt, protein or fibre), or supply too little energy (pregnant sows, for instance, are routinely fed a
Data from ten sources comprising 3,851 flocks were modelled to identify variation in levels of mortality in laying hens. The predicted increase with age was curvilinear with significant variation between the seven breed categories. Mortality was higher in loose housing systems than in cages and variable within system, confirming previous reports. Cumulative mortality (CM) was higher in flocks with intact beaks (χ2 = 6.03; df 1; p = 0.014) than in those with trimmed beaks. Most data were available for free-range systems (2,823 flocks), where producer recorded CM at 60–80 weeks of age averaged 10% but with a range from 0% to 69.3%. Life cycle assessment showed that the main effect of increased levels of hen mortality is to increase the relative contribution of breeding overheads, so increasing environmental burdens per unit of production. Reducing CM to levels currently achieved by the 1st quartile could reduce flock greenhouse gas emissions by as much as 25%. Concurrently this would enhance hen welfare and better meet the expectation of egg consumers. More research to understand the genetic x environment interaction and detailed records of the causes of mortality is required so that improved genotypes can be developed for different systems and different breeds can be better managed within systems.
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