Non-cage Systems Research Articles

Ir Douwe Ehlhardt 1936 – 2016

With great sadness we have lost a good friend and scientist. On February 1, 2016 Ir Douwe Arnold Ehlhardt passed away in a hospital in Amsterdam at the age of almost 80 years. Douwe, born in Leeuwarden on February 18, 1936 graduated at Wageningen University in 1961. After completing his military service, he started in 1963 his professional career at the Cooperative Poultry Breeder Institute (CPI) in Nuland. Here Douwe became secretary of the scientific breeding committee to advice members of the layer breeder’s cooperative on genetic selection issues. In 1971 Douwe became senior scientist at the Spelderholt Centre for Poultry Research in Beekbergen with a special focus on turkey research. Following the fast increase in broiler meat consumption during the sixties it was believed that turkey meat consumption would follow the same trend. This made Douwe to decide to visit Prof Karl Nestor in Wooster (Ohio). In 1972 he went to the USA and worked together with Prof Nestor at his institute to improve his knowledge on breeding, hatching, feeding, housing and disease control of turkeys. Back in The Netherlands, Douwe became secretary of the Dutch Branch of WPSA, which position he held until 1977. In that year he went for two and a half years with his family to Naivasha in Kenya where he, on behalf of the Dutch Government, built an applied poultry research station. After returning to The Netherlands Douwe was asked to become secretary of the European Federation of WPSA, a position he accepted in 1981 and remained in until 1993. During these twelve years he was involved with the organisation of the 7th European Poultry Congress in Paris (France) in 1986 and the 8th European Poultry Congress in Barcelona (Spain). A few months after the congress in Paris, Douwe received the ‘Chevalier de l'Ordre du Merite Agricole’ during a special event at the Spelderholt Centre for Poultry Research. This high decoration, handed over by the French Ambassador in The Netherlands, was given to Douwe because of his great contribution to the conference. During the eighties the Dutch poultry industry received increasing numbers of public comments on how layers were held in cages. Animal protection groups and activists fought for animal rights. Following many difficult discussions between poultry behaviour scientists in the governmental Spelderholt Centre for Poultry Research, animal protection people and governmental officials as well as politicians, Douwe Ehlhardt initiated research on keeping birds in the aviary system. He had to solve many issues including cannibalism, handling manure (including nitrogen emissions), in-house climate conditions as well as preventing floor eggs. Since then most of these problems have been resolved and, following the ban on layer cages in 2012, provide layer farmers an opportunity to keep layers efficiently in non-cage systems. Today more than 80 % of the layers in The Netherlands are kept in aviary systems. In 1993 Douwe was asked by the Dutch government to lead a poultry development project in Saudi Arabia. He accepted the offer and spent two years in Riyadh at the Ministry of Agriculture solving poultry husbandry problems in Saudi Arabia. In 1995 he rejoined Spelderholt but had to move to Lelystad when research activities on ruminants, pigs and poultry were concentrated in one research institute called ID-DLO. He worked there till his retirement in 2001. Ir Douwe Ehlhardt contributed a great deal to poultry research in The Netherlands and worldwide. We have lost an integral scientist, a friend to his colleagues and fellowworkers and a man who, due to his language skills, made people laugh. We will sadly miss him.

Keel-bone damage and foot injuries in commercial laying hens in Denmark

AbstractKeel-bone damage and foot injuries have a negative impact on welfare in laying hens. The extent of the problems in Danish commercial flocks of layers is unknown. Therefore, the aim of this study was to assess the current prevalence of keel-bone damage and foot injuries in Danish commercial flocks of laying hens and to investigate the effects of production system, housing system, hybrid and age. The occurrences of keel-bone damage, hyperkeratosis and missing toes were higher at 62 compared to 32 weeks of age, while the reverse was found for toe wounds, foot-pad lesions and bumble feet. There was no difference between barn and organic production systems in the risk of having keel-bone fractures and foot injuries, except that barn hens were more likely to have foot-pad lesions than organic hens (32 weeks: 16.1 vs 3.1%). Hens in multi-tiered systems were more likely to have keel-bone fractures compared to hens in single-tiered systems (62 weeks: 11.6 vs 4.9%). Of the four hybrids, Lohmann Brown Lite had a higher risk of keel-bone fractures, whereas bumble feet were found more frequently in Lohmann LSL Keel-bone damage and foot injuries are less common in Danish non-cage systems compared to most of the reporting presently available from other countries. We suggest transnational studies, aimed at identifying the causal factors of this discrepancy, to increase existing knowledge on how to reduce incidences of keel-bone damage and foot injuries.

Tree cover and injurious feather-pecking in commercial flocks of freerange laying hens: a follow up

AbstractInjurious feather-pecking in non-cage systems is a serious economic and welfare concern for the egg-producing industry. This study presents results from data of over 1,000 flocks from producers who supplied free-range eggs to McDonald's Restaurants Ltd UK between 2008 and 2013. These producers had a minimum 5% of the outdoor range planted in trees. We investigated the correlation between the plumage damage of end-of-lay hens with i) proportion of the total range planted with trees and ii) proportion of canopy cover within tree-planted areas. As tree canopy developed over the study period, we also investigated whether there were any changes in end-of-lay plumage-damage scores within farms, with year over the five years. There was a negative correlation between canopy cover and plumage damage at the end of lay, ie less canopy cover within tree-planted areas resulted in significantly worse plumage damage at the end of lay. There was no correlation between the amount of range planted and plumage damage at the end of lay. These results support the notion that it is the degree of shade and shelter (ie quality of cover) that is important to the hens rather than the absolute area. We did not find any association between year and end-of-lay plumage-damage scores. Due to commercial changes in supply, the proportion of farms providing data for ≥ 3 years was small, thereby limiting the data set with which to compare individual farms’ plumage-damage scores. It is hoped the relationship between year and plumage-damage score will be reexamined in a future study.

Opinion of Belgian Egg Farmers on Hen Welfare and Its Relationship with Housing Type.

Simple SummaryUntil 2012, laying hens in the EU were often housed in conventional cages that offered limited space and few opportunities to perform highly motivated behaviors. Conventional cages are now banned in the EU in order to improve animal welfare. In this study, egg farmers were surveyed (winter 2013–2014) to assess whether they perceived any changes in animal welfare since changing housing systems, what role hen welfare played in choosing a new housing system, and which aspects of hen welfare they find most important. The data show that the answers differ depending on which housing system the farmers currently use and whether they had used conventional cages in the past.As of 2012, the EU has banned the use of conventional cages (CC) for laying hens, causing a shift in housing systems. This study’s aim was to gain insight into farmers’ opinions on hen health and welfare in their current housing systems. A survey was sent to 218 Belgian egg farmers, of which 127 (58.3%) responded, with 84 still active as egg farmer. Hen welfare tended to be less important in choosing the housing system for farmers with cage than with non-cage systems. Respondents currently using cage systems were more satisfied with hen health than respondents with non-cage systems. Reported mortality increased with farm size and was higher in furnished cages than in floor housing. Feather pecking, cannibalism, smothering and mortality were perceived to be higher in current housing systems than in CC, but only by respondents who shifted to non-cage systems from previously having had CC. Health- and production-related parameters were scored to be more important for hen welfare as compared to behavior-related parameters. Those without CC in the past rated factors relating to natural behavior to be more important for welfare than those with CC. This difference in opinion based on farmer backgrounds should be taken into account in future research.

The table eggs and their quality in small-scale breeding

The purpose this study was to investigate quality of the table eggs, their damage and soiling in various age of the laying hens (47-62 weeks) during the second phase of the laying cycle. The object of the research was table eggs, egg white, egg shell, damage and soiling of the egg shell. The eggs were of the final laying hybrid ISA Brown reared in the non-cage system with deep litter and free range at small-scale breeding. In the breeding system with free range at small-scale conditions were secured requirements for laying hens in accordance with welfare principles. The eggs were collected each day at 4:00 pm. Weights of egg and egg shell samples of were measured on scales type KERN 440-35N. A white weight was calculated. Damage and soiling of eggs were investigated under the desk lamp lighting up to 100 W bulb. Statistical evaluation of the results was carried out in the program system SAS. From the existing conclusions of the various scientific and professional published works, it is known that both quality and safety are interrelated. In many works are the risk factors referred together as the quality standards. We found an important fact in assessing the trend of values of the egg shell weight, depending on the age of laying hens. Based on this fact, it can be assumed that the values of egg shell weight were not directly related to egg weight and egg white weight. It follows that the egg shell weight must be assessed comprehensively, and account must be taken of other factors. For the characteristics of the deformed egg shape has been one pc, representing 3.33% of the samples taken for analysis of eggs at 53 weeks of age of the total sampled eggs. In the following 56 weeks of age hens laying eggs there was not a deformed shape. The next subsequent sampling 59 weeks of age laying hens were recorded two pcs of eggs with deformed shape, i.e. 6.67%. At the last sampling of eggs at age 62 weeks, the number of eggs with deformed shape increased to three pcs, representing 10.0% of the sampled eggs for analysis. The sediments on the shell eggs were observed as variable ridge shapes of the shell matter. At the first sampling of eggs at age 47 weeks were found 2 pcs of this defect, representing 6.67% of the sampled eggs. The ridges on the egg shell belong to deviations of the natural shell associated with its texture. These defects of egg shell frequently occur depending on the age of laying hens but can also be caused by other factors. In our experiment was studied mainly the age factor of laying hens. It was interested from aspect of clarifying the relation between ridges on the egg shell and weight of the egg, white, egg, respectively. The results of investigated ridges on the egg shell showed that there occurred in every age of laying hens. Their highest number was recorded at age 59 and 62 weeks (5 pcs, i.e. 16.67% of the 30 egg samples). After 59 weeks of age was found also reduce the weight of the white and shell and at age 62 weeks of age was reduced egg shell weight. Egg production with calcareous sediments on the shell is probably hereditary. Currently, the consumer prefers the consumption of eggs with brown shell. Egg shell color is determined primarily by genetics of laying hens. The results of our experiments have shown that the occurrence of the dots on egg shell had a shade darker brown colour or bright dots, especially on the ends of the egg. The occurrence of dotted eggs was recorded in each assessed age of laying hens (5 - 7 pcs, i.e. 16.67 to 23.33%), while in the last, evaluated 62 weeks of age even up to 9 pcs. These dots and their occurrence are related to the intensity of pigment deposition in the shell cuticle. The process of distribution of pigment in egg shell is the same as is formed by packing egg shell and therefore the cuticle. With the increasing age of laying hens reduces the intensity of pigment deposition in the egg shell and increases of egg surface area, of the egg shell area, to which the pigment is stored. This fact is confirmed by our results especially at week 62 of age, when occurrence of pigment dots was the highest on the shell and also these eggs had the highest average weight.

Causes of keel bone damage and their solutions in laying hens

Keel bone damage (KBD) is a critical issue facing the contemporary laying hen industry due to the likely pain leading to compromised welfare and reduced productivity. Recent reports suggest that KBD, while highly variable and likely dependent on a host of factors, extends to all housing systems (including traditional battery cages, furnished cages and non-cage systems), genetic lines, and management styles. Despite the extent of the problem, the research community remains uncertain as to the causes and influencing factors of KBD. To combat these issues, the current review was produced following discussions from the 1st International Keel Bone Damage Workshop held in Switzerland in April 2014. This exercise sought to assess current knowledge, foster novel collaborations, propose unique methodologies and highlight the key areas where innovative research is needed. The following paper is based on the content of those discussions and presents nine recommendations for future research efforts.

Air Quality in Alternative Housing Systems May Have an Impact on Laying Hen Welfare. Part I-Dust.

The new legislation for laying hens in the European Union put a ban on conventional cages. Production systems must now provide the hens with access to a nest, a perch, and material for dust bathing. These requirements will improve the behavioral aspects of animal welfare. However, when hens are kept with access to litter, it is a concern that polluted air may become an increased threat to health and therefore also a welfare problem. This article reviews the literature regarding the health and welfare effects birds experience when exposed to barn dust. Dust is composed of inorganic and organic compounds, from the birds themselves as well as from feed, litter, and building materials. Dust may be a vector for microorganisms and toxins. In general, studies indicate that housing systems where laying hens have access to litter as aviaries and floor systems consistently have higher concentrations of suspended dust than caged hens with little (furnished cages) or no access to litter (conventional cages). The higher dust levels in aviaries and floor housing are also caused by increased bird activity in the non-cage systems. There are gaps in both the basic and applied knowledge of how birds react to dust and aerosol contaminants, i.e., what levels they find aversive and/or impair health. Nevertheless, high dust levels may compromise the health and welfare of both birds and their caretakers and the poor air quality often found in new poultry housing systems needs to be addressed. It is necessary to develop prophylactic measures and to refine the production systems in order to achieve the full welfare benefits of the cage ban.

Laying hen performance in different production systems; why do they differ and how to close the gap?Results of discussions with groups of farmers in The Netherlands, Switzerland and France, benchmarking and model calculations.

Free range and organic systems expose the laying hen more to unexpected events and adverse climatic conditions than barn and cage systems. In France, The Netherlands and Switzerland the requirements for a hen suitable to produce in free range and organic systems were discussed with farmers. The farmers preferred for these systems a more ‘robust’ hen, more specifically defined as a heavier hen with good eating capacity. Benchmarking of flocks in a web-based management program in The Netherlands from layer flocks finished in 2008 – 2013 indicated that in earlier years indeed mortality among organic and to a lesser extent free range hens was higher than among barn or cage hens. Feed conversion (kg feed/kg eggs) is higher, but the gap is closing. Improvements in management of the hens during rearing and in the layer phase in free range and organic systems seem to be important. Breeding companies take behaviour and performance in non-cage systems into account in their selection programs. Heavier hens need a diet with a lower protein to energy ratio. From model calculations we concluded that in organic systems a heavier hen might be economically profitable, as total feed costs are lower for the heavier hen then for a hen with a lower body weight requiring a diet with a high protein content. For conventional free range hens this is not the case as then the protein content can be adapted by synthetic amino acids. Field studies and cooperation between farmers and breeding organisations will have to show if a strain of heavier hens will be successful in the rather small organic market.

Determination of space use by laying hens using kinematic analysis

Two states in the United States now have legislation requiring that laying hens be provided with sufficient space to perform particular behaviors. To provide a framework for translating these performance standards into a space requirement, kinematic analysis was used to measure the amount of space needed for White Leghorn hens to stand, turn around 180°, lie down, and wing flap. Hyline W-36 hens (n = 9) were marked on the tops of their heads and the tips of both wings and 3 toes with black livestock marker. Each hen was then placed in a floor pen (91.4 × 91.4 cm) and filmed using 2 high-speed cameras. The resulting images were processed using a software program that generated 3-dimensional space use for each behavior. Because none of the hens lay down in the test pen, the 2-dimensional space required for lying was determined by superimposing a grid over videos of the hens lying down in their home cages. On average, hens required a mean area of 563 (± 8) cm2 to stand, 1,316 (± 23) cm2 to turn around, 318 (± 6) cm2 to lie down, and 1,693 (± 136) cm2 to wing flap. The mean heights used were 34.8 (± 1.3) cm for standing, 38.6 (± 2.3) cm for turning, and 49.5 (± 1.8) cm for wing flapping. However, space requirements for hens housed in multiple-hen groups in cage or noncage systems cannot be based simply on information about the space required for local movement by a single hen. It must also incorporate consideration of the tendency of hens in a flock to synchronize their behaviors. In addition, it must include not just local movement space but also the space that hens may need to use for longer-distance movements to access resources such as food, water, perches, and nest boxes.

Management approaches to reduce feather pecking in laying hens

The current paper summarizes recent findings on management approaches that reduce feather pecking in laying hens. Results from epidemiological studies as well as studies on single factors have been taken into account, from the period of 2005 up till now and older studies have been included where relevant. Feather pecking in laying hens is still a major problem and because of the development of an increasing number of flocks housed in non-cage systems and a possible future ban on beak trimming in some countries it is important to define effective management strategies. In general, recent studies provide additional evidence for factors associated with an increased or reduced risk for feather pecking compared with earlier work in this field. It has been confirmed that the rearing period is very important to prevent feather pecking in the laying phase. Management factors associated with a reduced risk for severe feather pecking are a reduced stocking density, diets with increased fibre contents, mash instead of pelleted feed, reduced light intensity, presence of good quality substrate, access to attractive outdoor runs and providing environmental enrichment to stimulate foraging and exploration behaviour. As feather pecking is a multifactorial problem, the interaction between management factors and between management and the genetic background of the bird is important and an area for further research. In addition, the transfer of knowledge from scientific studies to commercial practice an issue that should receive attention.

Canopy cover is correlated with reduced injurious feather pecking in commercial flocks of free-range laying hens

AbstractInjurious feather pecking in non-cage systems is a serious economic and welfare concern for the egg-producing industry. Here, we describe the first results from an ongoing collaborative project to improve range environment and welfare of laying hens(Gallus gallus domesticus)within the McDonald's Restaurants Ltd, UK supply base. The objective of this study was to investigate, in a commercial situation, the correlation between: i) proportion of range cover and ii) proportion of canopy cover, with plumage damage of end-of-lay hens. The assessment of plumage damage due to injurious feather pecking is a key animal-based welfare indicator for laying hens in non-cage systems. In 2007 and 2008, all laying-hen producers within the McDonald's Restaurants Ltd egg-supply base, were required to plant (if not present already), 5% of the total range area with blocks of trees ether side, and between 20-25 m from the laying hen house. Plumage damage at end of lay was positively correlated with mortality and flocks depleted in summer had less plumage damage at end of lay than flocks depleted in autumn or winter, possibly because of weather conditions at the time of placement. There was no correlation between the proportion (5-90%) of range cover and plumage damage at the end of lay, however, plumage damage was negatively correlated with percent of canopy cover within tree-planted areas. Providing a minimum of 5% tree cover, planted close to the house but with good canopy coverage, may be a feasible and practical method enabling producers to reduce plumage damage due to injurious feather pecking in their laying-hen flocks. Tree cover provision may also provide environmental benefits, such as soil stabilisation, reduced nutrient leaching and carbon sequestration.

Survey of egg producers on the introduction of alternative housing systems for laying hens in Flanders, Belgium

In the context of the European Union ban on battery cages by 2012, a survey was conducted among Flemish egg producers (60% response rate, 140 completed questionnaires) about the introduction and opinion of alternative housing systems. Belgium appears to be among the countries in the European Union that are slower to adopt alternative housing. Belgium's egg industry is thus likely to undergo drastic changes to comply with the 2012 deadline. As of 2010, the battery cage was the dominant housing system (56% housing units, 67% hens), followed by floor housing (33% housing units, 15% hens) and aviary (10% housing units, 15% hens), whereas colony cages and furnished cages were extremely rare. Future- and market-oriented production was the most important reason for choosing a certain type of alternative system, although the importance of hen performance and amount of labor seemed to increase. A quarter of the producers with battery cages had detailed plans to convert to an alternative system (most planned to install aviaries, followed by colony cages, furnished cages, and floor housing) by 2012. Many older farmers indicated that they would stop farming, whereas others found it more profitable to delay the conversion as long as possible. Apart from hen welfare, producers expressed a negative opinion (relative to battery cages) about noncage systems and, to a lesser extent, furnished cages. However, users of alternative systems reported being quite satisfied, except for the amount of labor and hen health. The housing system had several effects on user satisfaction: positive effect of flock size, negative effect of experience with battery cages, and negative effect of outdoor area on hen health. Although not all opinions were supported by evidence, such surveys provide feedback about the success of alternative systems in practice. This information is valuable to further improve these systems and to producers who have yet to convert. Moreover, producer attitude may determine the extent to which legally imposed changes in husbandry environment result in the desired improvement of hen welfare in practice.

Overall welfare assessment of laying hens: Comparing science‐based, environment‐based and animal‐based assessments

To increase the validity of evaluations and facilitate expansion and maintenance of assessment systems, we constructed a database of studies on the welfare of laying hens around the world. On the basis of this database, we devised a science-based welfare assessment model. Our model includes measurements, levels and weightings based on the scientific studies in the database, and can clarify the advantages and disadvantages of housing systems for laying hens from the viewpoint of the five freedoms. We also evaluated the usefulness of our model by comparing it with environment-based Animal Needs Index (ANI), another science-based model called FOWEL, and animal-based measurements. Our model showed that freedom from injury, pain and disease, and freedom from discomfort were more secure in the cage system, while non-cage systems scored better for natural behavior and freedom from fear and distress. A significant strong-positive correlation was found between the animal-based assessment and the total scores of ANI (rs = 0.94, P < 0.05), FOWEL (rs = 0.99, P < 0.05) or our model (rs = 0.99, P < 0.05), which indicate that these different approaches to welfare assessment may be used almost interchangeably to 'measure' a common property ('overall laying hen welfare'). However, assessments using our model and FOWEL were more sensitive than ANI and can be applied to cage systems, which suggest that our model and FOWEL may have added value.

Hen welfare in different housing systems

Egg production systems have become subject to heightened levels of scrutiny. Multiple factors such as disease, skeletal and foot health, pest and parasite load, behavior, stress, affective states, nutrition, and genetics influence the level of welfare hens experience. Although the need to evaluate the influence of these factors on welfare is recognized, research is still in the early stages. We compared conventional cages, furnished cages, noncage systems, and outdoor systems. Specific attributes of each system are shown to affect welfare, and systems that have similar attributes are affected similarly. For instance, environments in which hens are exposed to litter and soil, such as noncage and outdoor systems, provide a greater opportunity for disease and parasites. The more complex the environment, the more difficult it is to clean, and the larger the group size, the more easily disease and parasites are able to spread. Environments such as conventional cages, which limit movement, can lead to osteoporosis, but environments that have increased complexity, such as noncage systems, expose hens to an increased incidence of bone fractures. More space allows for hens to perform a greater repertoire of behaviors, although some deleterious behaviors such as cannibalism and piling, which results in smothering, can occur in large groups. Less is understood about the stress that each system imposes on the hen, but it appears that each system has its unique challenges. Selective breeding for desired traits such as improved bone strength and decreased feather pecking and cannibalism may help to improve welfare. It appears that no single housing system is ideal from a hen welfare perspective. Although environmental complexity increases behavioral opportunities, it also introduces difficulties in terms of disease and pest control. In addition, environmental complexity can create opportunities for the hens to express behaviors that may be detrimental to their welfare. As a result, any attempt to evaluate the sustainability of a switch to an alternative housing system requires careful consideration of the merits and shortcomings of each housing system.

The impact of different housing systems on egg safety and quality

A move from conventional cages to either an enriched cage or a noncage system may affect the safety or quality, or both, of the eggs laid by hens raised in this new environment. The safety of the eggs may be altered either microbiologically through contamination of internal contents with Salmonella enterica serovar Enteritidis (Salmonella Enteritidis) or other pathogens, or both, or chemically due to contamination of internal contents with dioxins, pesticides, or heavy metals. Quality may be affected through changes in the integrity of the shell, yolk, or albumen along with changes in function, composition, or nutrition. Season, hen breed, flock age, and flock disease-vaccination status also interact to affect egg safety and quality and must be taken into account. An understanding of these different effects is prudent before any large-scale move to an alternative housing system is undertaken.

Sustainability of egg production in the United States—The policy and market context

The US egg industry is being pressured from many directions to change its production practices, particularly to address concerns about hen welfare in conventional cage systems. Responding to similar pressures, in 1999, the European Union banned conventional laying cages starting in 2012. This now impending European ban has led to the development of several alternative housing systems. These include noncage systems like aviaries and modified (enriched or furnished) cages that include perches, areas in which the hens can forage and dustbathe, and nests. Understanding the European experience is valuable as the United States considers the future direction of the egg industry. In the United States, the proportion of eggs produced in alternative systems is small (less than 5% of output) but growing, in part due to market and political incentives for systems that provide hens with more behavioral freedom than conventional cages. Animal welfare, however, is only one element of a sustainable production system. Other elements include those related to public values, the environment, economics, worker health, and food safety and quality. Eggs are a primary source of animal protein globally, and the United States is the third largest producer of eggs in the world, behind China and the European Union. The national table egg flock comprises about 280 million hens housed in all regions but with approximately 60% of eggs produced in the 10 leading states. Adopting new housing systems will have substantial effects on costs and other aspects of egg production on both a regional and national scale, with some positive effects but also potential negative effects that need to be carefully considered. This paper discusses the US egg industry in the context of legislation and standards related to hen housing systems. It also addresses initiatives by retailers, nongovernmental organizations, and private certification organizations to shape production practices in the egg industry as well as how those initiatives might affect various aspects of the sustainability of egg production.

Influence of rearing and lay risk factors on propensity for feather damage in laying hens

1. Feather pecking is one of the major problems facing the egg industry in non-cage systems and is set to become even more of an issue with the European Union ban on the keeping of laying hens in barren battery cages which comes into force in 2012 and the prospect of a ban on beak-trimming. Reducing feather pecking without resorting to beak treatment is an important goal for the poultry industry. 2. We report here a longitudinal study that included over 335 500 birds from 22 free range and organic laying farms. Accelerated failure time models and proportional hazards models were used to examine the effects of a wide range of factors (management, environment and bird) on development of substantial feather damage in lay. Particular emphasis was placed on risk factors during rear and on practices that could feasibly be changed or implemented. 3. The age at which a flock exhibits substantial feather damage could be predicted both by factors in the environment and by early symptoms in the birds themselves. Factors that were associated with earlier onset of severe feather damage included the presence of chain feeders, raised levels of carbon dioxide and ammonia, higher sound and light levels, particularly in younger birds. Increased feather damage (even very slight) in birds at 17–20 weeks of age was also highly predictive of the time of onset of severe feather damage during lay. Increased feed intake also indicated that a flock was at risk of early severe feather damage. 4. Birds that stayed on the same farm for rearing and lay showed later onset of serious feather damage than those that experienced a change in farm from rearing to lay. However, an increased number of changes between rearing and lay (feeder type, drinker type, light intensity etc) was not associated with earlier onset of serious feather damage. Further research needs to be done on the role of the transition from rearing to lay as a risk factor for FP in lay.

Ascarid infections in laying hens kept in different housing systems

The present study was undertaken to investigate the prevalence of ascarid infections in Swedish commercial laying hens in 2004 and 2008 following a recent nationwide change to alternative housing systems but before anthelmintics became available. Also, the influence on prevalence of farm and flock characteristics and management was studied in 2004. The results showed that the overall prevalence was significantly higher in 2008 (38%; n = 64/169) compared with 2004 (24%; n = 44/186) (P = 0.001). Ascarid infections were rare in caged flocks, including furnished (enriched) cages, both years (2.4 to 4.3%), and were significantly more common in non-cage systems in both years (16.7 to 48.6% in 2004, and 28.6 to 77.1% in 2008 depending on the housing system). There was no significant difference in prevalence between hens kept on litter indoors and free-range/organic hens. The absence of a hygiene barrier at the entrance of the house or unit increased the risk of infection (P < 0.001), which suggests that parasite eggs were introduced horizontally to the farms. The risk of infection also increased with the age of equipment used in the barn; for example, the risk increased with an odds ratio of 7.5 (95% confidence interval = 2.3 to 25) when comparing equipment 1 year old with equipment ≥7 years old. The results of this study show that ascarid infections may re-emerge following a change to alternative housing. With the impending ban on conventional battery cages in the member states of the European Union, ascarid infections are likely to increase in importance and efficient control options such as hygiene barriers should be implemented on all farms.

Layer breeding strategies: an overview

Layer breeding companies apply selection criteria to improve over 30 traits important for commercial egg production. Intensive selection for egg production over the decades has resulted in a significant reduction in genetic and phenotypic variations in egg production, however the decrease in genetic variation observed in commercial lines are not yet critical. Peak production now approaches the biological limit of one egg a day, but in early production (at sexual maturity) and late production (persistency) genetic variation is still high. Including these traits in the selection criteria will improve the egg production in commercial birds. Due to high heritability and the absence of any significant negative effects on production parameters, residual feed consumption is used as selection criteria to improve the feed efficiency. Considerable research has been carried out on egg weight, eggshell strength and internal quality of the eggs and improvements have been made as a result of selection. With the reintroduction of floor system and increased consumer interest in processed eggs, in future more emphases have to be given to the eggshell strength and internal quality of the eggs. Poultry production in the unfavourable environmental conditions of the tropics is hindered by direct and indirect heat stress leading to a general depression in performance. Results on the utilisation of naked-neck and frizzle gene in high-ambient temperatures is encouraging, and, in future, will play an important role in production of layer lines suitable for overcoming such genotype-environment interaction. Feather pecking is an undesirable behaviour, which causes major problems in non-cage systems. Several authors have identified a hereditary basis of feather pecking behaviour, which is suggested by strain differences. Hence, selection of birds with no or very low tendency to perform feather pecking should reduce the incidence. Recent molecular genetic studies resulted in identification of QTL affecting different economic traits and identification of candidate genes causing variation in performance among birds. In future these findings will play a major role in further genetic improvement of layers without any negative effect.

The Economics of Regulations on Hen Housing in California

Beginning January 1, 2015, conventional cage housing for egg-laying hens is scheduled to be prohibited in California. We consider the economic implications of the new hen housing regulations on the California shell egg industry. Our data show that egg production is more costly using noncage systems than conventional cages. The main result of the new regulations will be a drastic reduction in the number of eggs produced in California, a large increase in egg shipments from out of state, little if any change in hen housing for eggs consumed in California, and little change in egg prices in California.