Assessing Welfare – Part 2

In October’s issue, we brought you an overview of the recent 5th International Conference on the Assessment of Animal Welfare at Farm and Group Level (WAFL), which was held at the University of Guelph and hosted by U of G’s Campbell Centre for the Study of Animal Welfare. Sponsored by the Poultry Industry Council, the conference had close to 300 delegates from more than 20 countries in attendance, presenting and discussing the most current knowledge on assessment and auditing of the welfare of animals in groups. The October issue focused particularly on broiler welfare assessment. Laying hen welfare was also well covered, and here we bring you some of the conference highlights of that work.

The latest research
The welfare of laying hens has received considerable attention in Canada recently. In March 2010, the Manitoba Egg Farmers announced a policy that moves away from conventional cages, and requires all egg farmers who build new facilities or undertake a major retrofit after 2018 to install enriched cages or another housing system that supports the Five Freedoms.  In May 2011, Egg Farmers of Canada named a brand new academic Chair in Laying Hen Welfare, Dr. Tina Widowski, at the University of Guelph. In the February 2011 issue of Canadian Poultry , we heard about Daniel Martel and his son Stéphane, who have inaugurated Quebec’s largest layer barn equipped with enrichable cages. Major changes toward improving layer welfare are happening across Canada in a short span of time – including policy changes.

When policy changes come into play, the outcomes of these changes require evaluation for optimization.

Evaluation involves characterizing the level of animal welfare within any system. Different approaches may be used to accomplish this, and in Europe, qualitative evaluations of welfare are getting a lot of attention. Dr. F. Neijenhuis of Wageningen UR, Livestock Research, has been working on a method of characterizing “animal discomfort” to evaluate trends across years on a national level for evaluation of animal welfare policy and prioritization of policy. This project was carried out in response to Europe’s Welfare Quality® project, which comprehensively assesses animal welfare on-farm, but which is not yet implemented for policy evaluation. 

In the context of this study, “discomfort” is defined by the researchers to mean when an animal fails to have positive experiences (e.g., fulfilment of behavioural needs, “natural behaviour”), or has negative experiences (e.g., elective surgeries such as beak or toe trimming, chronic stress), and refers to those forms of physical and mental health that can be established and substantiated scientifically. Poultry were analyzed in the years 2007 and 2011 (in addition to cattle, pigs, mink and horses). 

To analyze discomfort, three categories were used for severity, duration, and share of the population experiencing a given item, for between 10 and 40 items per species. Per species, two to five experts reached consensus on scores. Multiplication of the three figures identified items causing severe discomfort of longer duration for a large part of the population. For poultry, the researchers conclude that low-stimulus surroundings and restricted space cause the highest discomfort, and that this is quantifiable for any given country over time. This method is useful, says Neijenhuis, because when repeated, for each item differences in severity, duration, and/or proportion of the population can be identified, providing an overall indication of a trend in level of discomfort for the species. Ultimately, Neijenhuis hopes that this type of information can be used in Europe for evaluation of animal welfare policy and prioritization of policy.
 
How should we keep our birds?
Egg farmers are now well aware that new systems are available and emerging for housing laying hens – systems that can provide more space and stimulation and fulfil behavioural needs. But there are still many questions about how the systems perform and how hens perform within these systems. What are the real benefits to the birds? What are the welfare trade-offs, if any? 

Examining conventional cage design is one approach for identifying factors to take into account when designing systems that optimize hen welfare. Dr. Ruth Newberry of Washington State University and her research team have been using an epidemiological approach to examine relationships between cage design, feather cover and feather cleanliness of commercial laying hens. They obtained data on feather condition of White Leghorn hens in 167 commercial houses distributed across all regions of the United States, using a five-point scale for feather cover and a four-point scale for feather cleanliness. From each house, systematic data on cage dimensions and other aspects of the housing environment were also gathered. 

Feather cover was significantly greater in houses with frequent waste removal, cup drinkers or plain nipple drinkers rather than nipple drinkers with drip cups, incandescent rather than fluorescent lights, greater floor space allowance per hen, less feeder space per hen, lower cage floor slope, and lower cage height and in which hens had cleaner feathers. Feather cleanliness was greater in houses without evaporative cooling, with the Hy-Line W36 strain of White Leghorns, with shallower cages, and with taller cages. 

The study shows that multiple aspects of cage design and management affect feather cover and cleanliness, sometimes in unexpected ways. Knowing just which factors come into play is useful for design of new systems, conventional or enriched. This study reminds us that within any given housing systems there are a myriad of design features, and those that appear to be minor details can actually have dramatic effects.

The flip-side of conventional cages for hen housing is the free-run or aviary system, where hens have the run of an entire poultry house and/or multiple tiers within that house. Welfare and behaviour within these systems is being investigated by Dr. Parsons and his research team at the University of Iowa. They assessed use of a litter area in a multi-tier aviary, in relation to changes in welfare assessment parameters. Use of the litter area was video-recorded, and a subset of birds was selected from each section within the house chosen for welfare assessment and behaviour observations. Clinical scoring of bird health related to plumage, parasites, injuries and disease.

Approximately 154 per cent of birds went to the litter throughout the day, meaning that some birds visited more than once and indicating that litter is a valuable resource. Movement of the hens to and from the litter was affected by time of day and section of the house. It was also found that some welfare assessment parameters, such as keel bone injuries, changed over time within the same group of hens – more research is needed to determine risk factors.

Bone breakage within laying hen flocks presents a considerable welfare concern because of the potential for pain and effects on behavioural patterns. Although the risk for bone breakage at end of lay and depopulation is well known, it is less well known that there is also a risk for fractures during lay, particularly in extensive systems (i.e., free-run or aviary) due to impact against objects within the environment. 

Gemma Richards of the University of Bristol has been using radiography (X-ray technology) to assess keel bone fractures and assess fracture healing in live birds. Twenty-four Lohmann brown birds with varying degrees of keel fracture were taken from commercial facilities and housed in experimental facilities, and were X-rayed regularly over six weeks. Eighty per cent of birds entering the study with “new” fractures had healed after 35 days, and five birds incurred new breaks despite their original fracture status. Richards says that this technique provides valuable insight into the nature of keel bone fractures and the process of fracture healing in layers.

Another concern with moving to new housing systems involving larger groups is feather pecking. Elske De Haas at Wageningen University in the Netherlands has been assessing fearfulness, stress and feather damage in commercial laying hen parent flocks. Laying hen parent stock farms vary in flock size, stocking density and management practices, says De Haas, which can affect birds’ ability to cope with fear and stress and their propensity to feather peck. Furthermore, genetic origin can affect fearfulness and feather pecking. 

De Haas investigated whether farm conditions and genetic background affected behaviour and stress physiology of parent flocks of two commonly used commercial hybrids, Dekalb White and ISA Brown. Group size was either less than 6,000 or more than 6,000, but with similar stocking densities. The researchers assessed feather damage, fecal corticosterone metabolites and fearfulness by using a novel object test and a human approach test. 

The results of this study did not show a relationship between hybrid and farm conditions on fear and feather pecking for the breeds studied, although Dekalb White flocks approached a novel object sooner. However, a large variation in fecal corticosterone metabolites was found between farms, indicating effects of management on the ability to cope with fear and stress. De Haas stresses that, especially in parent stocks, high fearfulness and chronic stress should be avoided to maintain production and welfare. A possible route of improvement, says De Haas, can lie in improving human-animal interaction, as a negative response to a human in a test setting may indicate fear of the farmer in general.

Overall, improving laying hen welfare involves careful consideration not only of which housing system to employ, but also of the management of the system and the breed of bird used within the system. Furthermore, what seem to be minor details within any housing system can actually have a dramatic impact on behaviour, welfare and production, and interactions of these details can also come into play. 

As with all animal welfare issues, questions are never simple, and answers are often not clear-cut. As Canada moves forward with egg production, the new and varied hen housing systems will need to be carefully studied, and their design and management modified as issues are identified. 

The next WAFL Conference will be held in France in 2014, and an abundance of new information will presented there, to continue to help inform our decision making, guidelines and policies.