Differences between feather pecking and non-feather pecking laying hen flocks regarding their compliance with recommendations for the prevention of feather pecking – A matched concurrent case-control design

https://doi.org/10.1016/j.applanim.2019.104839Get rights and content

Highlights

  • In feather pecking flocks 53% of individual hens showed plumage damage.

  • Dry litter in a covered veranda and a low stocking density are preventive for FP.

  • The more recommendations are fulfilled, the lower the risk to get a FP flock.

Abstract

Feather pecking (FP) is a multifactorial problem in all housing systems. Using a case-control design we wanted to determine a set of variables which may be decisive for a flock to become case or control. At the same time, we expected that the prevention of feather pecking not only depends on certain factors, but also quantitatively on the extent of compliance with recommendations. Data from three cross-sectional studies were pooled, from which 165 flocks were allocated to cases (FP problem flocks) or controls (no FP problem). Control flocks had at least 98% of hens with a very good or nearly complete feather cover whereas in case flocks 10% or more of the hens had highly damaged feathers or featherless areas ≥ 5 cm² in at least one body region. From 32 potential preventive factors that had been recorded in all data sets, 18 factors passed univariable pre-selection and were presented to forward logistic regression analysis. The resulting model for 137 flocks (due to missing values) explained 41% of the variance, correctly classified 77% of cases and comprised four variables with an effect size of f = 0.8. A higher stocking density increased the likelihood of a ‘FP-problem’ whereas the presence of wooden perches and a littered veranda lowered it. Unexpectedly, a higher drinking place/hen ratio also predicted a FP problem. The results concerning wooden perches and drinking place/hen ratio might be due to indirect effects and should be further investigated. Non-FP flocks complied on average with 46.5% of recommendations (from a list of 13 factors), which was greater than FP-flocks (42.5%, P =  .036, U = 2537.500, n = 165, Mann-Whitney-U test, dCohen = 0.327). We conclude that the number of fulfilled recommendations as well as the combination of specific measures such as provision of a covered veranda with dry litter or reduced stocking density are important to prevent FP.

Introduction

Egg production systems in Europe are undergoing dynamic changes. One driving force is an increasing concern of consumers, legislators and producers with respect to laying hen welfare (Pettersson et al., 2016). In a number of EU countries beak trimming/treating is or will be banned by legal provisions (Sweden, Norway, Finland, UK and the Netherlands), voluntary agreements (Germany) or label guidelines (Austria). However, feather pecking (FP) is still a problem in all housing systems (e.g. Kjaer and Bessei, 2013; Nicol et al., 2013). Reported percentages of affected flocks at the end of lay range from 60% (de Haas et al., 2014: flocks with more than 10% of hens with moderate or severe feather damage in one body region) to 86% (Lambton et al., 2010: flocks in which severe FP was observed).

Severe feather pecking leading to feather loss can result in economic losses as a result of increased food consumption in defeathered birds (Leeson and Morrison, 1978; Tullett et al., 1980) and increased mortality (El-Lethey et al., 2000; Fossum et al., 2009; Heerkens et al., 2015) as well as in reduced animal welfare since FP is painful (Gentle and Hunter, 1990) and hens with feather damage are more susceptible to cannibalistic pecking (Green et al., 2000). A large number of studies have tried to identify risk factors for the occurrence of this undesirable behaviour (reviews by Nicol et al., 2013; Jung and Knierim, 2018). In brief, FP is influenced by the interaction between numerous environmental and genetic factors which mainly affect foraging behaviour and the ability to cope with stress (Rodenburg et al., 2013). Jung and Knierim (2018) listed 32 risk factors during the laying period whose significance were supported by epidemiological or experimental study results with at most one contradictory result. An additional 21 factors had heterogeneous effects in the laying period or they were not confirmed yet, and nine potential preventive factors proposed in practice recommendations have not been studied yet.

At the same time, for multifactorially caused problems, the number of risk factors on a farm may be at least as important as the presence of specific single risks. Support for this idea can be found in the results of Lambton et al. (2013) that farms employing more recommended management strategies had lower FP problems. Similarly, we assume that farmers have higher chances of maintaining a ‘non-FP-flock’ when they comply with a greater number of recommendations how to prevent feather pecking.

To analyse which potential set of variables may be decisive for a flock to become case or control we used a logistic regression. At the same time, we expected that the prevention of feather pecking not only depends on certain factors, but also quantitatively on the extent of compliance with recommendations.

Section snippets

Description of data used

Data from three cross-sectional studies on laying hens in non-cage systems recorded in the years 2004–2014 were available (Table 1). In all studies, flocks were visited when hens were between 30 and 78 weeks of age (Table 1). Management data were collected by interviews using questionnaires. This included general farm information (e.g. number of hen places), flock information (e.g. age at placement, hybrid), data on vaccinations and medical treatments, feeding (e.g. composition, phases),

Results

Plumage damage (score 2 or 1 in the HH and AP project or score 2 or 3 in the MS project) was found on average in 53% of individual birds from case flocks and in 0.5% of hens from control flocks. The study flocks are described with respect to the different independent variables in Table 3, Table 4.

In total, 18 of the original 32 variables passed the pre-selection procedure (Table 3, Table 4) and were presented to forward logistic regression analysis. The resulting significant model (χ2(4, n=137)

Discussion

This study used data from three cross-sectional studies to examine risk factors for the development of FP. The three included studies focused on the main challenges for laying hen farms regarding disease and animal welfare, one aspect being the problem of FP. The 165 included flocks were convenience samples that, however, reflected a wide and well distributed diversity of major conventional and organic non-cage egg production conditions in some European countries, while excluding frequently

Conclusion

The provision of dry litter in a covered veranda and lower stocking density in the hen house were identified as preventive measures against FP. Wooden perches were found to have a preventive effect on FP too, but it is not clear if this was rather due to indirect system related effects or the actual wooden perches. An unexpected negative impact of more drinking places needs further investigation. Our results showed that the chance to maintain a non-FP flock increases, the more recommendations

Declaration of Competing Interest

None.

Acknowledgement

Lisa Jung was financed by the doctoral program ‘Animal welfare in Intensive Livestock Production Systems’; the authors thank the Lower Saxony Ministry for Science and Culture.

Furthermore, the availability of data form the following projects is gratefully acknowledged:

‘Healthy Hens’ (financed by CORE Organic II Funding Bodies, being partners of the FP7 ERA-Net project, CORE Organic II, Coordination of European Transnational Research in Organic Food and Farming systems, project no. 249667),

References (42)

  • P.F. Johnsen et al.

    Influence of early rearing conditions on the development of feather pecking and cannibalism in domestic fowl

    Appl. Anim. Behav. Sci.

    (1998)
  • L. Jung et al.

    Are practice recommendations for the prevention of feather pecking in laying hens in non-cage systems in line with the results of experimental and epidemiological studies?

    Appl. Anim. Behav. Sci.

    (2018)
  • S. Lambton et al.

    The risk factors affecting the development of gentle and severe feather pecking in loose housed laying hens

    Appl. Anim. Behav. Sci.

    (2010)
  • S. Leeson et al.

    Effects of feather cover on feed efficiency in laying birds

    Poult. Sci.

    (1978)
  • C.J. Nicol et al.

    Differential effects of increased stocking density, mediated by increased flock size, on feather pecking and aggression in laying hens

    Appl. Anim. Behav. Sci.

    (1999)
  • C.J. Nicol et al.

    Influence of prior exposure to wood shavings on feather pecking, dustbathing and foraging in adult laying hens

    Appl. Anim. Behav. Sci.

    (2001)
  • C.J. Pötzsch et al.

    A cross-sectional study of the prevalence of vent pecking in laying hens in alternative systems and its associations with feather pecking, management and disease

    Appl. Anim. Behav. Sci.

    (2001)
  • V. Aerni et al.

    Effect of foraging material and food form on feather pecking in laying hens

    Br. Poult. Sci.

    (2000)
  • M.W.P. Bestman

    The role of management and housing in the prevention of feather pecking in laying hens. Network for animal health and welfare in organic agriculture

    Proceedings of the 4th NAHWOA Workshop, Clermont-Ferrand

    (2000)
  • M.W.P. Bestman et al.

    Health and welfare in dutch organic laying hens

    Open Access, Animals

    (2014)
  • B. Bilĉίk et al.

    Changes in feather condition in relation to feather pecking and aggressive behaviour in laying hens

    British Poultry Science Vol.

    (1999)
  • Cited by (0)

    View full text