Functional housing systems for high welfare in laying hens: promoting natural behaviors in safe environments

Lead Research Organisation: University of Bristol
Department Name: Clinical Veterinary Science


There are 36 million UK laying hens producing 10 billion eggs with a retail value of £1 billion. In the EU 335 million hens generate E10 billion, and globally there are nearly 5 billion hens producing over 1 trillion eggs. Egg production is a major wealth creator and a key element of global food production. In the EU, battery cage systems have been banned, with much of the production switched to free range systems (FRS). Similar legislation is proposed in many other countries, including India and the USA. FRS provide many health and welfare benefits to laying hens, however two major threats to welfare and production have recently emerged which require urgent action. Keel bone fractures effect on average 60% of hens in FRS, with some systems as high as 90%. These are painful and reduce productivity and profit. With up to 20 million UK hens suffering from keel fractures each year, the Farm Animal Welfare Committee regard this as the most serious problem of hen welfare. Injurious feather pecking (IFP) affects as many as half the hens in over three quarters of all FRS, resulting in pain, decreased egg production, increased feed consumption, and often leading to cannibalism and death. Beak trimming, the main means of controlling IFP, is now banned in a number of EU countries, with a UK ban proposed for 2016, leaving producers with no effective means of control. Urgent action is therefore needed to devise an alternative strategy to reduce levels of IFP. Welfare in laying hens remains a serious public concern, with over 75% of UK and EU citizens regarding hen welfare as inadequate.

We have shown that impacts with structures within housing systems during normal activities are the major cause of keel fractures. However, hazardous housing structures cannot be entirely eliminated, and reducing activity, as seen in battery hens, seriously impairs skeletal function. We have shown that FRS hens making greater use of the range are more likely to remain fracture-free. However, range use in many systems remains very low, and the potential benefits of ranging are not being realised. We hypothesise that increased range use will promote activity away from hazardous structures, improving bone strength and skeletal function, but avoiding injurious impacts which generate keel damage.
Similarly, we and others have indicated that ranging significantly reduces IFP, with an 89% drop in systems with substantial range use. Thus we hypothesise that action to increase range use will reduce incidence and severity of IFP, and encourage natural foraging behaviours.

The aim is to determine whether actions to increase activity and natural behaviours in a safe environment will substantially and significantly reduce keel fractures and IFP in laying hens. However, ranging and activity may have other health and production consequences, and these will be examined at flock and individual level, allowing us to determine the effects of range use on the overall wellbeing of hens and the economic impact for the producers.

This study will combine video monitoring, welfare assessments, cutting-edge activity logging developed in previous BBSRC funded research, and light-level monitoring technology provided by Biotrack, a leading animal monitoring specialist. We will compare normal FRS, enhanced FRS and barn systems to get a breadth of individual and flock activity, ranging and behaviours. For the first time, this will allow evaluation of range use and activity in flocks and individual hens in commercial production units, provided by Stonegate, our Industrial Partner, one of the UK's leading egg producers. By examining welfare outcomes of feather pecking behaviour, plumage scores and keel fractures, we can assess relationships with fracture incidence and IFP levels. We will further determine how activity relates to biomechanical, metabolic, physiological and radiological changes in bone, to better understand how exercise influences skeletal function in chickens.

Technical Summary

Keel bone fractures (KBF) and injurious feather pecking (IFP) are the major welfare and economic problems in free range laying hens, creating a very poor public perception of egg production and reducing profit for the industry. Studies show that up to 90% of hens suffer KBF in some free range systems (FRS), and most flocks have IFP affecting up to half of hens. Resolving these problems is urgent and timely, since the 2012 EU ban on battery cages increased use of FRS in the UK to over 20 million birds - equating around 14 million hens suffering bone breakage and 5 million suffering IFP each year. Proposed battery cage bans worldwide have raised this as a global issue. Also, a ban on beak trimming, the only effective control for IFP, in many EU countries, with a UK ban proposed, has further increased the urgency of this problem. Industry, legislators and welfare bodies are increasingly recognising many FRS as unsustainable. KBF is mostly due to impacts with housing structures during normal activity, and IFP is thought to originate as misdirected foraging behaviour combined with close hen proximity. There is evidence that greater time spent ranging away from the house reduces both KBF and IFP. This study hypothesises that increased activity away from housing structures and greater range use will reduce KBF by increasing bone strength whilst curbing hazardous collisions, and lessen IFP by promoting natural foraging behaviour discrete from other hens. The study will use a total of 12 free range, 12 enhanced free range and 12 barn systems to monitor flocks AND individual hens for activity in-house and on-range, and range use, by combining newly developed hen-mounted 3d-accelerometers and light-level monitors. We will relate these to keel KBF, IFP, pathogen load, overall health and skeletal function. This will provide evidence to inform production standards to help eradicate the two most serious welfare problems, to the benefit of hens, industry, retailers and consumers.

Planned Impact

Who will benefit, and how?

Laying Hens
The principal beneficiaries of this study are free range laying hens. In a recent analysis of UK flocks, we calculated that less than 12% of birds will remain unharmed by end of lay, with the vast majority suffering from keel bone fractures (KBF), injurious feather pecking (IFP) or both. This corresponds to 15 million hens suffering keel bone breakage and 8 million affected by injurious feather pecking in the UK. If similar figures apply globally, this leaves a total of 4.3 billion hens exposed to potentially avoidable suffering. This project aims to substantially reduce KBF and IFP through a better understanding of how they relate to range use and site specific activities. This study has the potential to benefit billions of hens worldwide within a 5-10 year time scale.

Egg producers
The UK consumes 11.5 billion eggs per year, valued at £1billion. With widely reported welfare problems, producers are acutely aware of their poor public image. Bone breakage and injurious feather pecking also result in wastage and reduced productivity, imposing an enormous financial burden. The egg industry will benefit from improved productivity, reduced wastage and the possibility of marketing eggs as "welfare friendly", enhancing profitability and public image. In the short term Stonegate expect to increase their market share by rapidly responding to our findings and marketing eggs produced by high-welfare hens, backed up by good scientific evidence. The proposed UK ban on beak trimming is strongly opposed by farmers groups such as the NFU, as there are no comparable measure to reduce IFP currently available. This study aims to provide such an alternative.

Retailers have expressed support for this study (see attached). Extensive surveys suggest that welfare problems in egg production have considerably hampered egg retail, and therefore enhanced welfare would be expected to generate an increased volume of sales throughout the sector.

UK egg annual trade deficit is approximately £120 million. If the UK become market leaders in sustainable and high welfare egg production, this will benefit industry and the UK economy. EU wide surveys suggest UK industry would gain increased market share across Europe for "welfare friendly" eggs.

Consumers and society
In EU wide surveys of the egg market, over half of respondents believed that laying hen welfare is bad or very bad, consider welfare important in their purchasing choices, and would pay extra for high welfare eggs. In our own recent survey of 1776 consumers, over 75% were concerned with hen welfare and would spend more on high welfare eggs. Clearly, welfare in egg production is a major concern, and clear improvements would benefit consumers and society.

Policy makers and welfare bodies
Strong evidence of improved health and welfare in laying hens would allow welfare bodies (such as the RSPCA and the BHWT), policy makers (such as FAWC, DEFRA and the Beak Trimming Action Group), industry bodies (such as BEA, BEIC, IEC, BFREPA, BEPA, NEMAL and the Soil Association) and assurance schemes (such as Freedom Foods and AssureWel), to make clear recommendations to government, industry and consumers on sustainable and ethical egg production based on sound scientific evidence. Our work on battery cages, feather pecking, transport, welfare at slaughter, and keel fractures have previously led to a number of legislative changes, changes in welfare standards, setting up of governmental enquiries, and other initiatives. As a result of this study, we would expect welfare standards to be modified within a 5 year time scale.

Training of technical and postdoctoral researchers will provide a skill resource translating into a number of research areas. Training is a key part of this study, and researchers have access to a wealth of expertise within the research team, and a unique opportunity to work with industry.
Description We have identified that the use of hen-worn light monitors are an effective means to determine whether the hen is sited inside the shed or outside on the range.
We have determined that the wearing of monitoring devices does not influence the behaviour of hens.
There is no relationship between the use of range enhancements and either the number of hens using the range, or the risk of keel bone fractures.
Exploitation Route Use of light monitors to track animals.
Sectors Agriculture, Food and Drink,Digital/Communication/Information Technologies (including Software)

Description Foundation for Food and Agricultural Research (US)
Amount $431,998 (USD)
Funding ID ID 550830 
Organisation Foundation for Food and Agriculture Research 
Sector Charity/Non Profit
Country United States
Start 03/2018 
End 02/2022
Description GENESIS: Modular Insect Bioconversion System for On-site Animal Feed Production
Amount £572,566 (GBP)
Funding ID 104387 
Organisation Innovate UK 
Sector Public
Country United Kingdom
Start 11/2018 
End 09/2020
Description Impacts of the rearing environment on keel bone integrity, spatial awareness abilities of laying hens
Amount $431,998 (USD)
Organisation Foundation for Food and Agriculture Research 
Sector Charity/Non Profit
Country United States
Start 11/2018 
End 10/2022
Description Modular Insect Bioconversion System for On-site Animal Feed Production 
Organisation Entomics Biosystems
Country United Kingdom 
Sector Private 
PI Contribution Running a feeding study to examine affects on health, welfare, behaviour and productivity
Collaborator Contribution Producing live insects in a bioconverter
Impact Funding only at this stage
Start Year 2018
Description Farming Today interview (BBC 4) 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact Interview for the BBC 4 radio show 'Farming Today', on the impact of keel bone fractures on laying hens and how accelerometers can be used to study the causes of these.
Year(s) Of Engagement Activity 2017
Description Radio interview on Radio 4 "Farming Today" 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact The interview was part of a showcase of welfare related work undertaken at the University of Bristol School of Veterinary Science. I was describing our BBSRC funded work looking at the influence of ranging in influencing welfare measures in laying hens. I described the sensing technology we use to assess location and activity, as well as discussing enrichments designed to increase range use.
Year(s) Of Engagement Activity 2016
Description Talk to Bristol University Vet students 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Undergraduate students
Results and Impact This was a talk to Vet students to showcase the type of research being carried out at the university and try and make them excited about research. It was also to show them that there are other activities to engage with after graduation if the thought of working in practice does not appeal to them.
Year(s) Of Engagement Activity 2020