Stress, serotonin, natural antibodies and coping styles of chickens predisposed to feather pecking

Stress response, peripheral serotonin and natural antibodies in feather pecking genotypes and phenotypes and their relation with coping style. By Jerine A.J. van der Eijk, Aart Lammers, Joergen B. Kjaer, T. Bas Rodenburg. 2019. Physiology & Behavior 199: 1-10.

Highlights

• Physiological & behavioral measures were studied in relation to feather pecking (FP).

• Stress response, natural antibody titers, corticosterone & 5-HT level were identified.

• FP genotypes differed in behavioral responses, 5-HT level & natural antibody titers.

• FP phenotypes differed in behavioral responses & 5-HT level.

• FP genotypes and FP phenotypes could not be categorized into coping styles.

Abstract

Feather pecking (FP), a serious welfare and economic issue in the egg production industry, has been related to coping style. Proactive and reactive coping styles differ in, among others, the stress response, serotonergic activity and immune activity. Yet, it is unknown whether genetic lines divergently selected on FP (i.e. FP genotypes) or individuals differing in FP (i.e. FP phenotypes) can be categorized into coping styles. Therefore, we determined peripheral serotonin (5-HT) levels, natural antibody (NAb) titers, behavioral and corticosterone (CORT) responses to manual restraint (MR) in FP genotypes (high FP (HFP), low FP (LFP) and unselected control (CON) line) and FP phenotypes (feather pecker, feather pecker-victim, victim and neutral). We further examined the consistency of and relationships between behavioral and physiological measures. FP genotypes differed in behavioral responses to MR, 5-HT levels and NAb titers, but not in CORT levels after MR. HFP birds had less active responses at adolescent age, but more active responses at adult age compared to LFP and CON birds. The CON line had higher 5-HT levels at adolescent age, while the HFP line had lower 5-HT levels than the other lines at adult age. Overall, the HFP line had lower IgM NAb titers, while the LFP line had lower IgG NAb titers compared to the other lines. FP phenotypes differed in behavioral responses to MR and 5-HT levels, but not in CORT levels after MR or NAb titers. Within the HFP line, feather peckers tended to have less active responses compared to neutrals at adolescent age, while victims had more active responses compared to the other phenotypes at adult age. Feather peckers had higher 5-HT levels than neutrals at adult age. Behavioral and CORT responses to MR were not consistent over time, suggesting that responses to MR might not reflect coping style in this study. Furthermore, proactive behavioral responses were correlated with reactive physiological measures and vice versa. Thus, it was not possible to categorize FP genotypes or FP phenotypes into specific coping styles.

Feather pecking genotype and phenotype affect behavioural responses of laying hens

Feather pecking genotype and phenotype affect behavioural responses of laying hens By Jerine A.J. van der Eijk, Aart Lammers, Peiyun Li, Joergen B. Kjaer, T. Bas Rodenburg, 2018. Applied Animal Behaviour Science 205: 141-150
Abstract

Feather pecking (FP) is a major welfare and economic issue in the egg production industry. Behavioural characteristics, such as fearfulness, have been related to FP. However, it is unknown how divergent selection on FP affects fearfulness in comparison to no selection on FP. Therefore, we compared responses of birds selected on low (LFP) and high feather pecking (HFP) with birds from an unselected control line (CON) to several behavioural tests (i.e. novel object (NO), novel environment (NE), open field (OF) and tonic immobility (TI)) at young and adult ages. Furthermore, the relation between actual FP behaviour (i.e. FP phenotypes) and fearfulness is not well understood. Therefore, we compared responses of birds with differing FP phenotypes. Feather pecking phenotypes of individual birds were identified via FP observations at several ages. The number of severe feather pecks given and received was used to categorize birds as feather peckers, feather pecker-victims, victims or neutrals. Here we show that HFP birds repeatedly had more active responses (i.e. they approached a NO sooner, vocalized sooner and more, showed more flight attempts and had shorter TI durations), which could indicate lower fearfulness, compared to CON and LFP birds at both young and adult ages. Within the HFP line, feather peckers had more active responses (i.e. they tended to show more flight attempts compared to victims and tended to walk more compared to neutrals), suggesting lower fearfulness, compared to victims and neutrals. Thus, in this study high FP seems to be related to low fearfulness, which is opposite to what previously has been found in other experimental and commercial lines. This stresses the need for further research into the genetic and phenotypic correlations between FP and fearfulness in various populations of chickens, especially in commercial lines. Findings from experimental lines should be used with caution when developing control and/or prevention methods that are to be applied in commercial settings. Furthermore, activity and/or coping style might overrule fearfulness within the HFP line, as HFP birds and feather peckers within the HFP line had more active responses. This might indicate a complex interplay between fearfulness, activity and coping style that could play a role in the development of FP.

Highlights

• The effect of feather pecking genotype and phenotype on fearfulness was studied.

• Responses of birds to behavioural tests were studied at young and adult ages.

• High feather pecking line had more active responses, suggesting lower fearfulness.

• Feather peckers had more active responses, suggesting lower fearfulness.

Dutch egg producers are learning to live without beak trimming

Dutch_farmers are learning to live without beak trimming

Poultry World, Aug 22, 2018

Beak treatments will formally be banned in the Netherlands from next year, but the market has moved ahead of legislation. Poultry World discovers how farms are managing the change.

From the beginning of September, members of the Netherlands’ largest egg assurance scheme, IKB EI, will not be permitted to keep hens with treated beaks.

This also includes infrared beak trimming. To this end, Avined decided to anticipate market demands as much as possible.

The German KAT (Association for Controlled Alternative Animal Husbandry) monitoring system has already prohibited the restocking of hens with trimmed beaks with effect from 1 January 2017.

Read more about the role of market forces, environmental enrichment, feed and light in Poultry World…

GroupHouseNet: webstream updates on beak trimming and tail docking

COST action GroupHouseNet Stakeholder Meeting

June 27th 2018

 

Schedule (Local time in Turkey: CET +1),

Webstreamed session:

09:00-9:05      Brief introduction to the Action and meeting, Action Chair Andrew M. Janczak

09:05-9:10      Introduction from the organiser, Sezen Ozkan

09:15-9:45      Challenges and possible solutions related to damaging behaviour in laying hens, Mia Fernyhough, RSPCA

09:50-10:20    Research on risk factors and prevention of damaging behaviour in laying hens, Elske de Haas, WUR

10:20-10:45    Break

10:50-11:20    Tail biting and actions to prevent tail biting in the EU, Copa Cogeca, Miguel

Angel Higuera, Director ANPROGAPOR, Madrid

11:25-11:55    European Commission project to reduce systematic tail-docking of piglets in

Member States, Desmond Maguire, European Commission, DG Health and Food Safety

 

How to join the webstream:

  1. Primary link: Ege university digital media server: http://stream.ege.edu.tr/canli2.html. This link can only be viewed with PC/notebook with enable flash player-supported internet browser (does not support mobile phone or tablet view).
  2. Second optionIn case there are any problems, we may use this Youtube link: https://www.youtube.com/channel/UCbgZZs7LslTIxC8880ppvew/live

 

Poultry Transport video released!

Poultry Transport video released!
made by Animal Transport Guides project

The practical video on how to best transport poultry, based on the guide to Good Practise ( click here)  for the transport of poultry and three dedicated Fact Sheets, is now available. This video provides practical advise to ensure that birds transported remain in good welfare, and is available with translated subtitles in 8 languages.

English video
French video
German
Greek

 

Italian
Polish
Romanian
Spanish

Interested on watching videos on Pig, Cattle,Horses and sheep transport? Click here

Hennovation project results

When research meets farming to lift welfare (article in Poultry World, dd 12-6-2018).

The EU-funded Hennovation project was an exercise in bringing egg farmers together with researchers to develop practical ways to improve welfare, as Tony McDougal discovers.

Researchers have partnered with farmers to draw up practical new measures for improving the health and welfare of farmed poultry.
The 2 ½ year EU-funded Hennovation project, which ended this autumn, has been finding ways to introduce practice-led innovation in sustainable animal welfare through the development of innovation networks.

The core of the project was more than 15 so-called “innovation networks”, involving producers and laying-hen processors, established in 5 EU countries – the Czech Republic, Spain, Sweden, the UK and the Netherlands. They looked at a range of technical challenges including feather loss through injurious pecking, red mites and handling hens at end-of-lay.

Read more at the Poultry World website.

Keel bone damage – COST ACTION

A new international research group (COST ACTION) has started to address the problem of keel bone damage in laying hens.

Overview

The KeelBoneDamage COST Action will provide the laying hen industry with the innovations in breeding, nutrition, and management necessary to resolve the problem of keel bone damage in order to meet the high standards of welfare and productivity demanded by the European community. The extremely high frequency and severity of keel bone damage represents one of the greatest welfare problems facing the industry, a position held by leading authorities of animal welfare, including the UK`s Farm Animal Welfare Committee (FAWC) and European Food Safety Authority (EFSA). The Action seeks to provide a platform for collaboration on the causes of keel bone damage and solutions to reduce their severity and frequency. Through coordination of a variety of mediums including meetings, training schools and scientific exchanges, our network brings a diverse mix of disciplines together to facilitate novel and trans-disciplinary discussions that will lead to an accelerated rate of discovery and achievements. Participants come from a variety of stakeholder groups including academic scientists, policy makers, non-governmental organizations, and industry.  The diversity of these partners will ensure that developments are directed into tangible outputs that improve animal welfare and farm productivity.

You can find more on its website. The website also contains some practical stakeholder information about records, recommendations and an online tool.

 

 

Towards a common conceptual framework and illustrative model for feather pecking in poultry and tail biting in pigs – 1. Introduction

This is post 1. “Introduction” of:

Towards a common conceptual framework and illustrative model for feather pecking in poultry and tail biting in pigs – Connecting science to solutions

Marc B.M. Brackea, T. Bas Rodenburgb, Herman M. Vermeera, Thea G.C.M. van Niekerka
a Wageningen Livestock Research
b Wageningen University, Dept. of behavioural ecology

Reading guide

This is one of 8 blog posts under the heading of: “Towards a common conceptual framework and illustrative model for feather pecking in poultry and tail biting in pigs – Connecting science to solutions”. It contains the following sections/posts:

  1. Introduction, specifying the need to compare feather pecking (fp) in layers and tail biting (tb) in pigs
  2. Terminology, specifying the various concepts involved in fp/tb.
  3. Overview of main similarities and differences between feather pecking and tail biting
  4. Farmer as a risk factor, emphasising, perhaps for the first time, that the farmer is a kind of ‘animal’ that is part of the problem (and the solution).
  5. Models, reviewing available conceptual models of fp and tb, as well as presenting a new ‘face model’.
  6. Disease framework, arguing that fp/tb may be regarded as a medical disorder, over and above being an abnormal behaviour per se.
  7. Evolution and domestication, emphasising the need to view fp/tb as a phenomenon an evolutionary and genetic background.
  8. References

The entire text (8 posts) can be downloaded as one pdf here.

1. Introduction

Feather pecking (fp) in poultry and tail biting (tb) in pigs are among the most persistent animal-welfare problems associated with intensive livestock farming. Both problems have been studied and reviewed extensively (e.g. fp: (Rodenburg et al., 2008; Nicol et al., 2013; Rodenburg et al., 2013); tb: (Schrøder-Petersen and Simonsen, 2001; Bracke et al., 2004a; EFSA, 2007b; Taylor et al., 2010; D’Eath et al., 2014; Valros, 2017)). Legislation and policy initiatives have been discouraging the continued performance of routine mutilations (beak treatment and tail docking for fp and tb respectively). However, both poultry and pig farmers generally find it difficult to stop mutilations and prevent and/or treat these injurious behaviours in intensive farming systems. Comparing fp and tb may help address these problems. However, few papers have compared the two forms of abnormal behaviour in detail. One notable exception is the fairly recent Open-Access publication by Brunberg et al. (2016). These authors discussed similarities and differences between fp and tb, and presented a general model which looks somewhat like an envelope. This publication is written for a scientific audience, and it is not easy to read for farmers and others interested in solving fp/tb such as vets, other farm advisors and NGOs. Also the ‘envelope-shaped’ model presented by Brunberg et al. (2016) is not as appealing as we would (ideally) like it to be. It mainly says that by nature both pigs and poultry are omnivorous generalists that have (had to) become production specialists via genetic selection and rearing in large-scale intensive systems applying a one-size-fits-all principle. According to Brunberg et al. both the physical and social environment (‘where you are’ and ‘who is with you’), together with animal-related factors (‘who you are’) determines ‘what you become’ in terms of fp or tb, i.e. a performer (pecker/biter), victim/receiver or a neutral animal. The authors also hypothesise that the gut-microbiota-brain axis may play a crucial role which should be investigated further. This is in accordance with the common view that fp and tb are multifactorial problems associated with the substantial discrepancy between the natural and the commercial environment resulting in a (seriously) deprived foraging (and/or feeding) motivation that eventually leads to fp/tb (and worse, i.e. cannibalism, if not curtailed adequately).

It is not entirely clear, however, why the model (figure) in Brunberg et al. (2016) should look like an envelope. When looking a bit more closely at the figure, the model appears to encompass everything (the animal, its history and its entire, physical and social, environment). Only upon more careful examination and in particular when reading the text itself do the further ramifications underlying the model become more clear. Since we feel the text may be rather inaccessible for practical application in problem solving, one objective of these blog posts, therefore, is to compare this model to other models, esp. those developed in our own organisation (Wageningen University & Research), in order to see if we can better highlight the available knowledge that should be used to (eventually help) solve the problem in practice. To this end we have also tried to make the information presented by Brunberg et al. (2016) more accessible, and we supplemented it with our personal expertise on fp/tb. It is important to emphasise, however, that the primary aim of this publication is to improve on the available conceptual frameworks to facilitate practical understanding of fp and tb so as to support solving the problem in the future. We do not, however, aim to present a tool box or cook book for solving fp/tb.

Reading guide

This was blog post nr. 1 under the heading of: “Towards a common conceptual framework and illustrative model for feather pecking in poultry and tail biting in pigs – Connecting science to solutions”. It contains the following sections/posts:

  1. Introduction, specifying the need to compare feather pecking (fp) in layers and tail biting (tb) in pigs
  2. Terminology, specifying the various concepts involved in fp/tb.
  3. Overview of main similarities and differences between feather pecking and tail biting
  4. Farmer as a risk factor, emphasising, perhaps for the first time, that the farmer is a kind of ‘animal’ that is part of the problem (and the solution).
  5. Models, reviewing available conceptual models of fp and tb, as well as presenting a new ‘face model’.
  6. Disease framework, arguing that fp/tb may be regarded as a medical disorder, over and above being an abnormal behaviour per se.
  7. Evolution and domestication, emphasising the need to view fp/tb as a phenomenon an evolutionary and genetic background.
  8. References

The entire text (8 posts) can be downloaded as one pdf here.

Acknowledgements

These blog posts have been made possible by the Hennovation project (HORIZON 2020 ISIB-02-2014 project, Grant no. 652638).

Towards a common conceptual framework and illustrative model for feather pecking in poultry and tail biting in pigs – 2. Terminology

This is post 2 on “Terminology” of:

Towards a common conceptual framework and illustrative model for feather pecking in poultry and tail biting in pigs – Connecting science to solutions

Marc B.M. Brackea, T. Bas Rodenburgb, Herman M. Vermeera, Thea G.C.M. van Niekerka
a Wageningen Livestock Research
b Wageningen University, Dept. of behavioural ecology

Reading guide

This is one of 8 blog posts under the heading of: “Towards a common conceptual framework and illustrative model for feather pecking in poultry and tail biting in pigs – Connecting science to solutions”. It contains the following sections/posts:

  1. Introduction, specifying the need to compare feather pecking (fp) in layers and tail biting (tb) in pigs
  2. Terminology, specifying the various concepts involved in fp/tb.
  3. Overview of main similarities and differences between feather pecking and tail biting
  4. Farmer as a risk factor, emphasising, perhaps for the first time, that the farmer is a kind of ‘animal’ that is part of the problem (and the solution).
  5. Models, reviewing available conceptual models of fp and tb, as well as presenting a new ‘face model’.
  6. Disease framework, arguing that fp/tb may be regarded as a medical disorder, over and above being an abnormal behaviour per se.
  7. Evolution and domestication, emphasising the need to view fp/tb as a phenomenon an evolutionary and genetic background.
  8. References

The entire text (8 posts) can be downloaded as one pdf here.

2. Terminology

In the next posts we will summarise similarities and differences between feather pecking (fp) in laying hens and tail biting (tb) in pigs, taking Brunberg et al (2016) as a starting point. We will also characterise the different models that have been proposed before on fp/tb. Building on this we will argue why we think that fp/tb may/should be regarded as a medical/mental disorder, provided the medical framework maintains an evolutionary and scientific perspective on fp/tb.

This post aims to characterise the underlying concepts and criteria, so as to illustrate that giving crisp definitions may not be as easy as it may seem to be at first sight.

Note: We will use the label ‘fp/tb’ in the remainder of these related posts to refer to the communal problem. It is difficult to provide an overarching term for fp and tb together. Most existing terms are too wide: Abnormal behaviour, injurious behaviour and harmful-social behaviour, e.g. because there are other forms of abnormal behaviour and because there are other forms of injurious behaviours like aggression (e.g. vulva-biting in sows) and abrasive behaviours (injuries resulting from making contact to flooring or pen fittings; cf fin injuries in farmed fish (Noble et al., 2012; Stien et al., 2013; Pettersen et al., 2014; Folkedal et al., 2016)).

An outbreak of injurious fp/tb requires a specification of the start and end point, i.c. presence of injuries. Here, again, the observer may play a significant role: the detection of injuries depends e.g. on the inspection frequency and quality (e.g. method & expertise) of the observer. The observer also plays a role in so-called early-detection and in decision-making as to when and what treatment is to be started to counteract an on-going outbreak.

It should also be emphasized that fp/tb is a process, where different types of animals are involved. In order to start, one ‘neutral’ animal must become an actor (pecker/biter) showing fp/tb behaviour towards a victim/receiver resulting in a fp/tb wound. When the outbreak escalates more and more individuals become involved and/or wounds become progressively severe, potentially leading to the death of the victim (such that the fp/tb may at some point be called ‘cannibalism’). Wounds may also get infected, thereby aggravating the impact on productivity and welfare. Some animals in a fp/tb pen may not get involved. These may be labelled ‘neutrals’. In addition, Brunberg et al. (2016) use the term ‘controls’ for animals in neighbouring pens which are not affected by fp/tb. These different types of individuals involves are not fixed over time. E.g. both neutrals and controls are labels that may changes over time (Daigle et al., 2015), i.e. animals that were neutrals/controls today, may become actors or victims tomorrow, and individuals may be both actor and victim at some point in time (or even at the same time). When an outbreak ends, both actors and victims may return to being ‘neutrals’, even though it is generally recognised that the probability of recurrence is much bigger in groups that have previously experienced fp/tb problems, as if the ‘set points’ of such animals have changed irreversibly. Because of this rather irreversible state-change it is important to differentiate between prevention, what is done to prevent an outbreak, and curative treatment, what is done to stop an outbreak that has occurred.

A final term used in these posts is the word ‘model’, by which we primarily mean a figure intended to explain fp/tb. Ideally, the model should not only illustrate the mechanism and the types of individuals involved, and where/how it goes wrong (e.g. that fp/tb is a multifactorial problem), but also provide answers to the other 3 why questions (evolution, function, ontogeny). Ideally, also the model should explain anomalies (i.e. apparently ‘strange’ facts) and generate testable predictions. The ideal model should also be effective in communicating what is the (e.g. welfare or production) problem associated with fp/tb and provide suggestions regarding prevention and/or treatment. Also, a model is better if it uses a stronger, more intuitively appealing metaphor, such that it is easily remembered, not only by scientists, but also by other stakeholders, i.c. farmers, their advisors, and NGOs (see e.g. cartoons at http://www.featherwel.org/). However, besides addressing all of these aspects, a good model should not be complex, but rather explain fp/tb in the most parsimonious way possible.

Reading guide

This was blog post nr. 2 under the heading of: “Towards a common conceptual framework and illustrative model for feather pecking in poultry and tail biting in pigs – Connecting science to solutions”. It contains the following sections/posts:

  1. Introduction, specifying the need to compare feather pecking (fp) in layers and tail biting (tb) in pigs
  2. Terminology, specifying the various concepts involved in fp/tb.
  3. Overview of main similarities and differences between feather pecking and tail biting
  4. Farmer as a risk factor, emphasising, perhaps for the first time, that the farmer is a kind of ‘animal’ that is part of the problem (and the solution).
  5. Models, reviewing available conceptual models of fp and tb, as well as presenting a new ‘face model’.
  6. Disease framework, arguing that fp/tb may be regarded as a medical disorder, over and above being an abnormal behaviour per se.
  7. Evolution and domestication, emphasising the need to view fp/tb as a phenomenon an evolutionary and genetic background.
  8. References

The entire text (8 posts) can be downloaded as one pdf here.

Acknowledgements

These blog posts have been made possible by the Hennovation project (HORIZON 2020 ISIB-02-2014 project, Grant no. 652638).

Towards a common conceptual framework and illustrative model for feather pecking in poultry and tail biting in pigs – 3. Overview

This is post 3 on “Overview of main similarities and differences between feather pecking and tail biting” of:

Towards a common conceptual framework and illustrative model for feather pecking in poultry and tail biting in pigs – Connecting science to solutions

Marc B.M. Brackea, T. Bas Rodenburgb, Herman M. Vermeera, Thea G.C.M. van Niekerka
a Wageningen Livestock Research
b Wageningen University, Dept. of behavioural ecology

Reading guide

This is one of 8 blog posts under the heading of: “Towards a common conceptual framework and illustrative model for feather pecking in poultry and tail biting in pigs – Connecting science to solutions”. It contains the following sections/posts:

  1. Introduction, specifying the need to compare feather pecking (fp) in layers and tail biting (tb) in pigs
  2. Terminology, specifying the various concepts involved in fp/tb.
  3. Overview of main similarities and differences between feather pecking and tail biting
  4. Farmer as a risk factor, emphasising, perhaps for the first time, that the farmer is a kind of ‘animal’ that is part of the problem (and the solution).
  5. Models, reviewing available conceptual models of fp and tb, as well as presenting a new ‘face model’.
  6. Disease framework, arguing that fp/tb may be regarded as a medical disorder, over and above being an abnormal behaviour per se.
  7. Evolution and domestication, emphasising the need to view fp/tb as a phenomenon an evolutionary and genetic background.
  8. References

The entire text (8 posts) can be downloaded as one pdf here.

3. Overview of main similarities and differences between feather pecking and tail biting

Table 1 shows an overview of similarities and differences between feather pecking (fp) in poultry (i.c. laying hens) and tail biting (tb) in pigs (i.c. weaned and growing/fattening pigs).

Table 1 is based primarily on Brunberg et al. (2016) and supplemented with our own (esp. MB and TvN) knowledge about fp and tb (also as presented on the henhub website www.henhub.eu). The table is intended to summarise the most relevant similarities and differences between fp (in hens) and tb (in pigs), and thus support decision making in dealing with fp/tb in practice.

The key risk in fp/tb is the fact that both laying hens and pigs are originally omnivorous generalists that have been become production specialists in feed intake and food conversion in intensive farming conditions. The motivation for fp/tb relates to a frustrated foraging need, which is modulated by a whole array of different risk factors, hence resulting in this multifactorial welfare issue. In addition to similarities the table also identifies a number of differences between fp in layers and tb in pigs, e.g. we don’t have genetically selected lines for tail biting comparable to the high and low fp lines in poultry. Hence, an experimental model to study tb in more detail is currently largely lacking (though pigs selected for social breeding value (high indirect genetic effects for growth) showed considerably less ear biting, tail damage, aggression and enrichment manipulation (Camerlink et al., 2015), and may thus in principle be suited to be used to study tb experimentally in more detail).

The table may perhaps be improved upon further by specifying relationships between the items specified as risk factors (in the left column) and the different responses identified in the process of fp/tb (in the right column; cf (Fraser, 1987a)).

Another suggestion relates to the many risk factors that may hamper practical problem solving. While scientific experiments necessarily vary only a few risk factors in order to reliably examine which factors may affect fp/tb, a tentative suggestion for solving the multifactorial fp/tb problem could be to try to formulate multifactorial solutions. This may be esp. relevant when monofactorial solutions fail to solve the problem. However, an important drawback of this approach is that it may essentially remain unclear which factors are accountable for any (positive or negative) results. When a multifactorial approach is working, it may be possible to tease out in subsequent research the relative contribution of the different risk factors. When it doesn’t work, that may be the end of the road for that particular type of farming (given the constraints imposed).

Table 1. Comparing risk factors and animal responses related to feather pecking (fp) in poultry (laying hens) and tail biting (tb) in pigs, taking Brunberg et al. (2016) as a starting point, supplemented with own author expertise (marked as *). Common risk factors (similar across species, specified between brackets when ‘unknown’) are followed by notable differences between Hens and Pigs (specified on the next lines). Black characters: risk increasing factors; green: risk decreasing factors (benefits); red (in the column ‘risk factors’): particularly welfare-reducing risk factors. ‘No’: means that the opposite reduced fp/tb.; behav.: behaviour; envir.: environment; decr.: decreased; incr.: increased; HFP: high fp line/breed; LFP: low fp line; TIM: tail-in-mouth; w: weeks; d: days; mo: months. The cells in column ‘Responses’ are not directly (horizontally) related to the risk factors. Responses are stacked: more positive behaviours are presented at the bottom; worst (form of escalation, i.e. cannibalism) is shown on top. Responses are related to ‘type of animal’ (victim, actor, neutral) (with welfare aspects specified at the level of the type-of-animal label). Poor welfare responses are shown in red (in the column ‘responses’). See the text for a more detailed description of how to read the table.

Type of factor Risk factors (Multifactorial, related to the type of factor, i.e. environment-, group- & animal based) Responses (behav., physiology, pathology & welfare, related to type of animal, i.e. victim, actor, neutral) Type of animal
Envir.-based Modern large-scale specialised farms Victim: fear, pain (during outbreak), stress, sickness (during treatment, recovery) Victim
Barren pen (no proper foraging material, straw), large discrepancy between intensive farming envir. and the natural envir./envir. of evolutionary adaptation Cannibalism
(Partly) slatted floor
Hens: (Litter)
Pigs: Concrete
(Wound) infection
Indoors*
Hens: Range (may provide foraging opportunities and reduce stocking density)
Pigs: – (Outdoor area may provide rooting substrate (soil), fibre (pasture), but not necessarily)
Production loss (reduced growth)
Hens: Egg laying (reproduction)
Pigs: Growth (production)
One size fits all (food, climate*)
Standardised feed, optimised for average individual (vs indiv. needs); perhaps probiotics may treat fp/tb
Hens: –
Pigs: No phase feeding; decr. feeding frequency predicted tb outbreaks 9 w later; tb victims made more feeder visits 2-5w prior to tb
Appearance
Hens: Deteriorating feather cover
Pigs: Tucked tails
Feed changes and ‘hiccups‘ in providing feed (unpredictable frustration) Decreased tryptophan, serotonin levels
Feed type; Reduced feeding time, not ground, concentrated feed, less fibre
Hens: Pellets give more fp than fine ground feed; no mash/pecking materials; high E diet; no feathers in diet (acting as fibre, incr. feed passage)
Pigs: Contradictory results (liquid/pellets/meal) but straw reduces tb & is consumed
(Fp/tb) Wound(s)
Hens: Esp. tail, body (not back of head)
Pigs: Tail (possibly ears, flanks, legs)
Protein, mineral (NaCl) deficiency; supra-nutritional NaCl may alleviate fp/tb
Hens: Deficiency of crude protein, amino acids, minerals (Na, Ca)
Pigs: Nutritional imbalance incr. tb
Feeder space, feed competition (bite/peck to get access to feed) Salivation (pH incr.; alleviate peptic ulcers)
Rearing conditions (both poor rearing conditions and a backdrop from enriched rearing conditions to deprived conditions later in life)
Hens: Absence of litter around 5w, high stocking densities, rearing on wire floor
Pigs: More piglets/stockperson, fostering, no straw in farrowing pen, reduced feeder space during rearing gives more tb later in life; multi-litter rearing decr. manipulative behav.; providing straw during rearing and then depriving pigs of straw later is also considered a risk factor
[Microbiota composition?]
Hens: HFP has different microbiota composition than LFP; feather eating changes gut microbiota;
Pigs: Unknown
(Pen size, pen design)
Hens: (Large)
Pigs: (Small)
Escalation of tp/tb (outbreak)
Group-based (envir.- & animal based) Group housing
Hens: (Very) large groups (10-100.000 birds)
Pigs: Small (~10 pigs)
Arousal, restlessness, excitement (positive), fear & avoidance (negative).
Hens: Cut feathers increased fp
Pigs: Blood tail model (rope) increased (tail) biting behav.
High stocking density
Hens: More fp in largest groups (15-120 birds)
Pigs: (Not uniform results)
Cognition, (social) learning, (synchronisation; copy-behaviour; stimulus enhancement)
Farm health status (any (major) stressor/immune suppressor probably)
Hens: Vaccination (specific immune stimulation) when young may incr. fp as adults; LFP have better immunocompetence; e.g. E. Coli incr. severe fp
Pigs: Better health status reduces tb; straw reduces infections
Prevalence/intensity:
Hens: Fp on 86% of UK flocks; SFP esp. when adult; fp up to 135 bouts/bird/hr; 3 severe pecks/min
Pigs: Tb on 30-70% of farms; fanatic biters bite 11-25% of time
Mutilation (3 aspects are relevant: 1. Method used; 2. Amount of tissue removed; 3. Age of treatment; esp. 2nd aspects is relevant as risk factor)

Hens: Beak treatment (previous beak trimming (may remove larger/smaller part of the beak), now infrared beak treatment) (Note: In poultry, as it were the (future) actor is mutilated)

Severe fp (SEP)/tb

Hens: –

Pigs: Three types of (severe/injurious) tb: two-stage (starting with TIM), sudden forceful, and obsessive (fanatic)

Pigs: Tail docking (longer or shorter part of the tail) (Note: in pigs as it were the (future) receiver is mutilated by removing the tail) Actor: (Excitement, pleasure [during outbreak], pain, stress [during treatment])
Hens: Pecker
Pigs: Biter
Actor, performer
History of fp/tb (once an outbreak has occurred, the likelihood of another outbreak increases; animals are never the same again after an outbreak; (irreversibly) changed set points) Object-direction:
Hens: Towards feathers
Pigs: Towards the tail
Animal-based (Bred for) very high production-efficiency (genetics, breeds) (esp. genetic motivation of feed-related behav.; behavioural need to species-specific foraging behav); fp/tb has moderate heritability (~0.2) Neutral (in same pen)/control (on other pen):
Neutral as a biter in spe: boredom, frustration, behavioural deprivation, esp. of foraging motivation
Neutral / control
Hens: (Eggs)
Pigs: Lean meat; neutrals have different genetics
Gentle manipulation
Hens: Gentle fp is prevalent in young birds, decr. with age
Pigs: Tail in mouth (TIM),
Domesticated 5-6000 years ago; bred in 50 years of intensive selection from foraging generalists (omnivorous (variable diet; need to explore)) to meat & egg producing specialists; fp/tb not selected against; tb&fp are correlated to production, but not in the same way Pen-mate directed exploration
Hens: (Deteriorated) plumage condition
Pigs: Wet tails
Hens: Male peckers had higher body fat; female peckers had earlier onset of lay; HFP: Better growth, lower total egg mass, decr. feed efficiency
Pigs: Lower backfat, lean tissue growth
Consummatory behav.:
Hens: Feather eating (more in HFP)
Pigs: –
Being different
Hens: Plumage colour (standing out from others; incidental pigmented birds were more often victims)
Pigs: [Lame pigs get bitten]
Object/substrate-directed exploration/foraging in accordance with nature, showing natural behav. (50-60% of time)
Hens: Scratching, pecking
Pigs: Rooting, biting
Personality
Hens: Peckers appear more proactive, fearful (in open field), stress (cortisol shows variable results); more foraging & walking when young incr. fp as adults; HFP more active; mobility to get to the nestboxes (i.e. too calm birds are at risk for fp)
Pigs: Low backtest responders showed less pen-mate manipulation; biters more sitting & kneeling 6d prior to tb; victims more posture changes 6 d prior to tb; tail posture (tucked) may predict tb 2-3d before outbreak
Sex, probably females more active performers
Hens: All females
Pigs: Mixed/uni-sex; males receive more tb; uncastrated males are more likely to become fanatic biters (1 study)
Age: Onset around sexual maturity (also then shifting nutritional needs)
Hens: Adult (16-80wks); progesterone (& oestrogen) incr. up to 18w incr. fp; testosterone decr. fp; SFP ~20w in females, but not males
Pigs: Young, prepubertal (<5-6mo); perhaps associated with teething*
Body weight
Hens: –
Pigs: Biters are lighter; victims tend to be heavier before tb (later decr. growth)

Reading guide

This was blog post nr. 3 under the heading of: “Towards a common conceptual framework and illustrative model for feather pecking in poultry and tail biting in pigs – Connecting science to solutions”. It contains the following sections/posts:

  1. Introduction, specifying the need to compare feather pecking (fp) in layers and tail biting (tb) in pigs
  2. Terminology, specifying the various concepts involved in fp/tb.
  3. Overview of main similarities and differences between feather pecking and tail biting
  4. Farmer as a risk factor, emphasising, perhaps for the first time, that the farmer is a kind of ‘animal’ that is part of the problem (and the solution).
  5. Models, reviewing available conceptual models of fp and tb, as well as presenting a new ‘face model’.
  6. Disease framework, arguing that fp/tb may be regarded as a medical disorder, over and above being an abnormal behaviour per se.
  7. Evolution and domestication, emphasising the need to view fp/tb as a phenomenon an evolutionary and genetic background.
  8. References

The entire text (8 posts) can be downloaded as one pdf here.

Acknowledgements

These blog posts have been made possible by the Hennovation project (HORIZON 2020 ISIB-02-2014 project, Grant no. 652638).