Effect of acute heat stress on cognitive performance of chickens in a feed-related discriminant task.

Little is known about immediate and long-lasting effect of acute heat stress on chicken cognition. Thirty-five, 9-week-old birds were trained to differentiate two cone colours; white (rewarded, R; with feed underneath) and black (unrewarded, UR; empty). The sixteen birds that learnt the task were randomly assigned to three temperature regimens (TR: 22-24 °C (control), 30-32 and 36-38 °C for 3h/day) for three consecutive days during which rectal (RT), wing (WT) and eye (ET) temperatures were monitored. After the 3 h of exposure, birds were allowed to rest for 1 h before the commencement of the discriminant task. The latencies to open the cones (R and UR) and proportion of cones opened were recorded. A long-lasting effect was tested a week after exposure to TR. TR had a significant effect on RT, WT and ET. The motivation to turn over R cones was weaker in birds exposed to 36-38 °C than birds exposed to 22-24 °C. Also, the proportion of R cones opened were fewer in birds that experienced TR of 36-38 °C compared to birds exposed to 22-24 °C and 30-32 °C specifically on two out of the three cognitive test days (Days 1 and 3). Latency and proportion of UR cones opened was not affected by TR. RT, WT and ET were all negatively and significantly correlated with latency to open the UR cones. Previous exposure of birds to three TR had no effect on the latency to open both cones but the proportion of R cones opened was greater in birds exposed to 30-32 °C compared to the 22-24 °C birds. In conclusion, an immediate (36-38 °C) and long-lasting effect (30-32 °C) of acute heat stress was associated with a weak motivation to perform feed related discrimination task.

Determinants of biosecurity practices in French duck farms after a H5N8 Highly Pathogenic Avian Influenza epidemic: The effect of farmer knowledge, attitudes and personality traits.

Biosecurity is crucial for infectious disease prevention, more importantly in the absence of vaccination. The need for improving the implementation of biosecurity practices was highlighted in French duck farms following the 2016-2017 H5N8 Highly Pathogenic Avian Influenza (HPAI) epidemic. Farmers have multiple reasons for not implementing biosecurity practices: external (time, money) and internal (socio-psychological). The purpose of this study was to determine how sets of socio-psychological factors (i.e. knowledge on biosecurity and avian influenza transmission, attitudes, personality traits, social background) affect the adoption of on-farm biosecurity practices. Biosecurity practices and socio-psychological determinants were assessed during 127 duck farm visits, in South West France, using both questionnaires and on-farm observations. Factorial analysis of mixed data (FAMD) and hierarchical clustering analysis (HCA) identified three groups of farmers with different socio-psychological profiles: the first group was characterized by minimal knowledge, negative attitudes towards biosecurity, little social pressure and a low level of conscientiousness. The second group was characterized by more extensive experience in poultry production, higher stress and social pressure. The third group was characterized by less experience in poultry production, better knowledge and positive attitudes towards biosecurity, increased self-confidence and orientation towards action. The first group had a significantly lower adoption of biosecurity measures than the two other groups. A better understanding of the factors involved in farmers' decision-making could improve the efficiency of interventions aiming at improving and maintaining the level of on-farm biosecurity in the duck industry.

Factors influencing chicken farmers' decisions to implement prevention and control measures to reduce avian influenza virus spread under endemic conditions.

The ongoing circulation of Highly Pathogenic Avian Influenza (HPAI) H5N1 poses a threat to both poultry and public health. Adapting the constructs of the Health Belief Model (HBM) framework, we investigated perceptions of backyard, commercial broiler and layer chicken farmers to implement HPAI prevention and control measures in Bangladesh. Two cross-sectional studies were conducted in 2016 and 2017 on 144 backyard, 106 broiler and 113 layer chicken farms. Using Structural Equation Modelling, we modelled the direct and indirect effects on farmers' perceptions on taking HPAI prevention and control actions. Our results indicate that farmers of different chicken production systems have different decision-making processes. While perceived barriers to the implementation of prevention and control measures (e.g. wearing protective equipment when handling chickens) prevented both broiler and backyard farmers to adopt interventions, perceived benefits of measures (e.g. maintaining high biosecurity will reduce the risk of birds becoming sick) strongly influenced commercial farmers' decisions, but not backyard farmers' decisions. Information provided on HPAI through media, meetings or via information campaigns played an important role in farmers' decision-making in all production systems. Outcomes of this research can be used to tailor advice on HPAI control and prevention to different poultry farming groups by accounting for specific factors influencing their decision-making, instead of using one-size-fit-all communication approach.

Preventing zoonotic influenza H5N1 in human: Pictorial versus literal health communication methods.

Outbreaks of avian influenza H5N1 in poultry occurred in Africa's poultry and 16 countries have reported human infections globally. Intensified human-animal interactions necessitate correct communication of health messages to reduce zoonotic infection. This work was done to determine differences between pictorial and literal health education communication. Cross-sectional survey using literal and pictorial questionnaires in LBMs and poultry farms was carried out among respondents based on matching criteria. Responses were scored and analysed with probability of independence using Chi square test and pairwise correlation. The degree of knowledge of clinical signs in birds, species affected, communication means and biosecurity were good, that of the post-mortem signs was poor with increasing potentials of human exposure to virus-rich visceral tissues from slaughtered sick birds. Marked differences exist for the various items listed within each knowledge field, the odds of having correct responses from pictorial were better than with literal respondents. Risky practices were still practised in the LBMs despite the good degree of knowledge of hygiene and biosecurity. Knowledge and implementation does not always correlate and pictorial representation out surpasses literal method in communicating potential zoonotic H5N1 influenza A infection to the undiscerning public.

Understanding attitude, practices and knowledge of zoonotic infectious disease risks among poultry farmers in Ghana.

Zoonotic infectious diseases (ZIDs) are increasing globally, and livestock farmers in low- and middle-income countries are at particularly high risk. An evaluation of farmer's behaviour on farms can be used to identify the risk factors and to develop tailored control strategies. This study documents the knowledge of zoonotic poultry diseases (ZPD) among 152 poultry farm workers (respondents) from 76 farms in the Ashanti region of Ghana and assessed their on-farm attitude and practices that increase their risk to exposure of ZPD. The median age of respondents was 29 years, 91.4% (n = 139) had a formal education, and 80.9% (n = 123) had worked on the farm for more than 1 year. The majority of farms (n = 69, 90.8%) had multiple flocks and 27.6% (n = 21) kept other animals, of which 57.1% (n = 12) were pigs. The majority of respondents had good knowledge about poultry diseases but not about ZPD. A higher level of education and longer work experience improved respondents' knowledge of poultry and ZPD. Although respondents identified the wearing of personal protective equipment (PPE) as a major ZPD preventive measure, the majority did not put that knowledge into practice. Most farms (71.1%, n = 54) had no footbath and 55.3% (n = 42) deposited farm-waste on the farm. While 97.4% (n = 148) of respondents washed their hands after working, only 48.7% (n = 74) wore protective footwear, 2.7% (n = 4) wore overalls, 2% (n = 3) wore nose masks and none (n = 0) wore gloves. The husbandry practices and attitude of farmers expose them to pathogens on the farm and increase their risk of becoming infected with ZPD in the sub-region. The results from this study could be used to promote human health among farm workers in Ghana.

Keel bone fractures induce a depressive-like state in laying hens.

In commercial flocks of laying hens, keel bone fractures (KBFs) are prevalent and associated with behavioural indicators of pain. However, whether their impact is severe enough to induce a depressive-like state of chronic stress is unknown. As chronic stress downregulates adult hippocampal neurogenesis (AHN) in mammals and birds, we employ this measure as a neural biomarker of subjective welfare state. Radiographs obtained longitudinally from Lohmann Brown laying hens housed in a commercial multi-tier aviary were used to score the severity of naturally-occurring KBFs between the ages of 21-62 weeks. Individual birds' transitions between aviary zones were also recorded. Focal hens with severe KBFs at 3-4 weeks prior to sampling (n = 15) had lower densities of immature doublecortin-positive (DCX+) multipolar and bipolar neurons in the hippocampal formation than focal hens with minimal fractures (n = 9). KBF severity scores at this time also negatively predicted DCX+ cell numbers on an individual level, while hens that acquired fractures earlier in their lives had fewer DCX+ neurons in the caudal hippocampal formation. Activity levels 3-4 weeks prior to sampling were not associated with AHN. KBFs thus lead to a negative affective state lasting at least 3-4 weeks, and management steps to reduce their occurrence are likely to have significant welfare benefits.

Knowledge, attitudes, and practices associated with avian influenza along the live chicken market chains in Eastern China: A cross-sectional survey in Shanghai, Anhui, and Jiangsu.

The avian influenza (AI) virus of the H7N9 subtype emerged in China in 2013. Live bird markets (LBMs) selling live meat chickens were indicated to present a high-risk of the virus dissemination. This study aimed to quantify the level of knowledge, attitudes, and practices (KAP) on AI and to measure the associated risk factors among different actors along the live chicken market chain within H7N9-affected Eastern provinces in China. A cross-sectional survey was conducted in these provinces from June to July 2014. Structured questionnaires about KAP on AI were delivered to chicken farmers, chicken vendors, and consumers in LBMs. Multivariable generalized least squares regression models were developed to identify predictors of KAP scores among different actors. Our results indicate that KAP scores of chicken farmers were generally higher than those of chicken vendors. Chicken farmers who worked for more than 15 years had significantly lower total KAP scores than those who worked for less than 6 years. Chicken farmers who worked more than 15 hrs in a day had significantly lower attitude scores than those who worked less than 6 hrs. For chicken vendors, females and individuals > 35 years old had significantly lower knowledge scores compared to the reference categories. Practice scores were significantly higher in female vendors and those vendors who also conducted slaughter compared to males and vendors who did not conduct slaughter. Consumers who bought chicken at least once every month had better risk awareness compared to those who bought chicken at least once every week. In addition, female consumers had significantly better practice scores than male consumers. In conclusion, risk-based health promotion interventions should be developed and implemented by animal health agencies (targeting farmers and vendors) and public health agencies (targeting frequent and male consumers) to prevent transmission of H7N9 along the market chain in China.

What drives the choice of poultry market channel and the change of purchase behavior due to highly pathogenic avian influenza outbreaks?

In Indonesia, market channels play an important role in food security in poultry meats. This review explains Indonesian consumers' choice of market channels to purchase poultry, and consumer concern of food scares and food safety in their consumption due to highly pathology avian influenza (HPAI) outbreak. The survey was conducted for the traditional and the modern channels and involves a sample of 1096 respondents in the Greater Jakarta Area. The logistic regression analysis reports the model proved that the substantial findings in the choice for the modern poultry market channel are the price/quality relationship, the safety feature, and the level of consumer trust. Some variables explaining the change in purchase behavior due to HPAI outbreaks are similar to the results of the choice of market channel. This study shows that the developed assessment can be used by the government to make the poultry supply more safe.

Risk perceptions of public health and food safety hazards in poultry husbandry by citizens, poultry farmers and poultry veterinarians.

Differences in risk perceptions of public health and food safety hazards in various poultry husbandry systems by various stakeholder groups, may affect the acceptability of those husbandry systems. Therefore, the objective was to gain insight into risk perceptions of citizens, poultry farmers, and poultry veterinarians regarding food safety and public health hazards in poultry husbandry systems, and into factors explaining these risk perceptions. We surveyed risk perceptions of Campylobacter contamination of broiler meat, avian influenza introduction in laying hens, and altered dioxin levels in eggs for the most commonly used broiler and laying hen husbandry systems in Dutch citizens (n = 2,259), poultry farmers (n = 100), and poultry veterinarians (n = 41). Citizens perceived the risks of the three hazards in the indoor systems higher and in the outdoor systems lower than did the professionals. Citizens reported higher concerns regarding aspects reflecting underlying psychological factors of risk perception compared to professionals. Professionals indicated a relatively low level of personal control, which might imply risk denial. Of the socio-demographic characteristics, gender and childhood residence were associated with risk perceptions. The influence of other factors of risks perception are discussed. It is suggested that risk perceptions of all stakeholder groups are influenced by affect, stigma, and underlying values. To adapt current or new husbandry systems that can count on societal support, views of key stakeholders and multiple aspects such as animal welfare, public health, food safety, and underlying values should be considered integrally. When trade-offs, such as between animal welfare and public health have to be made, insight into underlying values might help to find consensus among stakeholders.

Small Poultry Flocks in Alberta: Demographics and Practices.

The distribution, composition, and management characteristics of small "backyard" poultry flocks may have important implications in the spread of both avian diseases and zoonoses of public health concern. Although the prevalence of small poultry flocks has increased in Alberta, Canada, in recent years, there is minimal demographic information available for these populations. To gain initial epidemiologic insight into this growing population and potential areas of risk, a survey was conducted to characterize the sector. Information on flock demographics and bird health, as well as production and biosecurity practices, were gathered and analyzed from 206 surveys, representing respondents from 43 counties. These results revealed great diversity of both owners and flocks, characterized by wide variations in flock sizes and composition. Laying hens were the most commonly reported type of bird (93.4%), followed by ducks and geese (35.3%), turkeys, (33.8%), and broiler chickens (33.1%). Notably, 58.1% of owners reported having more than one type of bird in their flock, with many owners never, or only sometimes, separating flocks based on species or purpose. Personal consumption (81.8%) and sale of eggs (48.2%) were the most frequently cited purposes for owning a flock. Our findings suggest that owners in Alberta are predominantly new to production; most (73.1%) have kept birds for less than 5 yr and 25.6% for less than 1 yr. Flock health parameters revealed inconsistent use of medical interventions, such as vaccinations, treatments, and veterinary consultation. Data on the sourcing, housing, and movement of birds, as well as movement of people and visitors, reveal substantial potential for contact to occur directly and indirectly between flocks and humans. Additionally, basic husbandry and biosecurity practices were found to be inconsistent and often inadequate, highlighting important gaps and opportunities to improve the health of Alberta's small poultry flocks and mitigate risks to public health. These quantitative and qualitative results provide a baseline characterization of the sector and identify risks and challenges that may serve to inform the development and delivery of future study and interventions.

Cultural Practices Shaping Zoonotic Diseases Surveillance: The Case of Highly Pathogenic Avian Influenza and Thailand Native Chicken Farmers.

Effectiveness of current passive zoonotic disease surveillance systems is limited by the under-reporting of disease outbreaks in the domestic animal population. Evaluating the acceptability of passive surveillance and its economic, social and cultural determinants appears a critical step for improving it. A participatory rural appraisal was implemented in a rural subdistrict of Thailand. Focus group interviews were used to identify sanitary risks perceived by native chicken farmers and describe the structure of their value chain. Qualitative individual interviews with a large diversity of actors enabled to identify perceived costs and benefits associated with the reporting of HPAI suspicions to sanitary authorities. Besides, flows of information on HPAI suspected cases were assessed using network analysis, based on data collected through individual questionnaires. Results show that the presence of cockfighting activities in the area negatively affected the willingness of all chicken farmers and other actors to report suspected HPAI cases. The high financial and affective value of fighting cocks contradicted the HPAI control policy based on mass culling. However, the importance of product quality in the native chicken meat value chain and the free veterinary services and products delivered by veterinary officers had a positive impact on suspected case reporting. Besides, cockfighting practitioners had a significantly higher centrality than other actors in the information network and they facilitated the spatial diffusion of information. Social ties built in cockfighting activities and the shared purpose of protecting valuable cocks were at the basis of the diffusion of information and the informal collective management of diseases. Building bridges with this informal network would greatly improve the effectiveness of passive surveillance.

The Perceived Value of Passive Animal Health Surveillance: The Case of Highly Pathogenic Avian Influenza in Vietnam.

Economic evaluations are critical for the assessment of the efficiency and sustainability of animal health surveillance systems and the improvement of their efficiency. Methods identifying and quantifying costs and benefits incurred by public and private actors of passive surveillance systems (i.e. actors of veterinary authorities and private actors who may report clinical signs) are needed. This study presents the evaluation of perceived costs and benefits of highly pathogenic avian influenza (HPAI) passive surveillance in Vietnam. Surveys based on participatory epidemiology methods were conducted in three provinces in Vietnam to collect data on costs and benefits resulting from the reporting of HPAI suspicions to veterinary authorities. A quantitative tool based on stated preference methods and participatory techniques was developed and applied to assess the non-monetary costs and benefits. The study showed that poultry farmers are facing several options regarding the management of HPAI suspicions, besides reporting the following: treatment, sale or destruction of animals. The option of reporting was associated with uncertain outcome and transaction costs. Besides, actors anticipated the release of health information to cause a drop of markets prices. This cost was relevant at all levels, including farmers, veterinary authorities and private actors of the upstream sector (feed, chicks and medicine supply). One benefit associated with passive surveillance was the intervention of public services to clean farms and the environment to limit the disease spread. Private actors of the poultry sector valued information on HPAI suspicions (perceived as a non-monetary benefit) which was mainly obtained from other private actors and media.

Parents and early life environment affect behavioral development of laying hen chickens.

Severe feather pecking (SFP) in commercial laying hens is a maladaptive behavior which is associated with anxiety traits. Many experimental studies have shown that stress in the parents can affect anxiety in the offspring, but until now these effects have been neglected in addressing the problem of SFP in commercially kept laying hens. We therefore studied whether parental stock (PS) affected the development of SFP and anxiety in their offspring. We used flocks from a brown and white genetic hybrid because genetic background can affect SFP and anxiety. As SFP can also be influenced by housing conditions on the rearing farm, we included effects of housing system and litter availability in the analysis. Forty-seven rearing flocks, originating from ten PS flocks were followed. Behavioral and physiological parameters related to anxiety and SFP were studied in the PS at 40 weeks of age and in the rearing flocks at one, five, ten and fifteen weeks of age. We found that PS had an effect on SFP at one week of age and on anxiety at one and five weeks of age. In the white hybrid, but not in the brown hybrid, high levels of maternal corticosterone, maternal feather damage and maternal whole-blood serotonin levels showed positive relations with offsprings' SFP at one week and offsprings' anxiety at one and five weeks of age. Disruption and limitation of litter supply at an early age on the rearing farms increased SFP, feather damage and fearfulness. These effects were most prominent in the brown hybrid. It appeared that hens from a brown hybrid are more affected by environmental conditions, while hens from a white hybrid were more strongly affected by parental effects. These results are important for designing measures to prevent the development of SFP, which may require a different approach in brown and white flocks.

Salmonella awareness and related management practices in U.S. urban backyard chicken flocks.

Raising chickens in urban settings is a growing phenomenon in the United States. The United States Department of Agriculture's (USDA) National Animal Health Monitoring System (NAHMS) conducted a cross-sectional study to better understand health and management of privately owned chicken flocks, and Salmonella awareness among chicken owners, in three urban settings-Denver, Colorado; Los Angeles, California; and Miami, Florida. Feed stores in each city were visited by data collectors during summer 2010, and customers who owned chickens were asked to complete a questionnaire. A convenience sample of 449 feed store customers was selected, and 382 (85.1%) customers participated in the study. For analysis, a stratified random sample was assumed, with the strata being individual feed stores. Median flock sizes were 5, 11 and 19 chickens in Denver, Los Angeles and Miami, respectively. In all three cities, over three-fourths of flocks contained table egg chicken breeds on the day the questionnaire was completed. In Denver, 20.4% of flocks had another species of bird present in addition to chickens, compared with 65.6% of flocks in Los Angeles and 53.6% of flocks in Miami. At the time of data collection in 2010, less than 50% of respondents in Miami and Los Angeles (40.0 and 30.2%, respectively) were aware of a connection between poultry contact, such as contact with chicks or ducks, and Salmonella infection in people, compared to 63.5% of respondents in Denver. Urban chicken flock owners who completed the questionnaire in English were more likely to be aware of the connection between poultry contact and Salmonella, compared with respondents who completed the questionnaire in Spanish (OR=3.5). The likelihood of Salmonella awareness was also higher for respondents who had heard of USDA's Biosecurity for Birds educational campaign and for respondents who sold or gave away eggs from their flocks (OR=2.5 and 2.8, respectively). Study findings demonstrate the importance of reaching the Spanish speaking population when creating educational outreach programs to reduce Salmonella infections in people who have live poultry contact.

Backyard chicken keeping in the Greater London Urban Area: welfare status, biosecurity and disease control issues.

1. The aim of the study was to collect baseline data on welfare, biosecurity and diseases of backyard chickens kept in the Greater London Urban Area (GLUA), United Kingdom (UK). 2. A total of 65 backyard chicken flock-keepers were recruited from May to July 2010 through adverts on websites, at City farms, veterinary practices and pet feed stores and surveyed by means of a questionnaire. A total of 30 responses were suitable for analysis. 3. Information on keepers' and flocks' characteristics, housing and husbandry practices and owners' knowledge of health problems in chickens and zoonotic diseases was collected. A welfare assessment protocol was developed and the flocks assessed accordingly. 4. Results showed that chickens were generally provided with living conditions that allowed them to perform their natural behaviours. 5. Most of the flock owners did not comply with the regulations of the Department for Environment, Food and Rural Affairs (Defra) on the feeding of catering waste. 6. Disease prevention measures such as vaccination and biosecurity, including limiting the access of human visitors, wild birds and rodents to the flocks were rare. 7. A lack of avian and zoonotic disease knowledge and awareness among the owners has implications for disease control and highlights the need for improved communication between owners, authorities and veterinarians.

Effect of methionine supplement on physical responses and neurological symptoms in broiler chicks fed grass pea (Lathyrus sativus)-based starter ration.

Starter feeding experiments of broiler chicks with raw grass pea (Lathyrus sativus L.) supplemented with different levels of DL-methionine were undertaken for 4 weeks to assess the toxicity of grass pea-based feed and to correlate it with neurological symptoms. Four hundred fifty day-old broiler chicks were divided into two groups and were given formulations containing 35% (ration I) or 98.5% (ration II) grass pea, respectively. Each ration included controls and treatments with added methionine of four different concentrations. Feed intake, weight gain and feed conversion efficiency (FCE) were much higher in ration I than in ration II and these parameters significantly improved by addition of methionine in both rations. Significant increase of neurological signs with higher grass pea intake and significant reduction of acute neurological signs with addition of methionine were observed. Tolerance for grass pea was enhanced with increasing methionine in the diet and with age. Despite a similarity in the initial intake, a significant (p0.05) increase in the final feed intake by the chicks with methionine addition was found in both rations. These results suggest that methionine can improve a grass pea-based diet for broiler chicks and especially can protect young chicks from neurological symptoms.

Effects of social disruption on physical parameters, corticosterone concentrations, and immune system in two genetic lines of White Leghorn layers.

Farm management practices such as increasing group size and mixing of unfamiliar chickens may cause social disruption and affect bird well-being. To examine genetic-associated physical and physiological differences in response to social disruption, 2 strains of White Leghorn hens were used in the study [i.e., HGPS (line selected for high group production and survivability) and DXL (DeKalb XL commercial line)]. Social disruption was created when hens were 50 wk of age by increasing group size from 4 hens (control) to 8 hens (experimental) per cage and providing an unstable social environment by moving 2 hens weekly between cages within the same line (experimental hens only). At 58 wk of age, hens were feather-scored. After euthanization, BW and the right adrenal gland weight were collected (n = 10 per treatment). Adrenal gland weight was adjusted for BW, and adjusted adrenal weight was used for analysis. Plasma corticosterone was quantified using RIA. The T-lymphocytes (CD4+ and CD8+) were measured using flow cytometry. Results showed that average feather cover score was greater for DXL hens than HGPS hens in both the unstressed (P < 0.05) and stressed treatment (P < 0.01). There was no difference in BW in DXL and HGPS hens between the control and the social disruption treatments. However, the relative adrenal weight of HGPS hens tended to be lower than control hens after social disruption (0.05 > P < 0.10). Plasma corticosterone was significantly lower in both strains following social disruption (P < 0.01). The T-lymphocyte ratio (CD4+:CD8+) was greater in HGPS hens than DXL hens post social disruption (P < 0.05). The data indicate that the 2 strains of hens reacted differently in terms of the adrenal system and immunity in response to social disruption. Hens selected for longevity with docile behaviors and high productivity, such as HGPS hens, provide a useful tool for improving animal well-being.

Social stress in laying hens: differential dopamine and corticosterone responses after intermingling different genetic strains of chickens.

White Leghorn chickens were genetically selected for high (HGPS) or low (LGPS) group productivity and survivability. The selection resulted in two genetic lines with marked opposite changes in cannibalism and flightiness when housed in multiple-colony battery cages without beak trimming. The objective of the study was to examine whether the genetic selection differentially affected the neuroendocrine system of chickens from different strains in response to social stress. Based on the previous studies, social stress was induced by randomly pairing 17-wk-old hens from three genetic lines, i.e., HGPS, LGPS, and Dekalb XL (DXL), to form three mixed-line combinations. At 24 wk of age, the concentrations of plasma dopamine (DA) and corticosterone (CORT) showed no differences in DXL hens housed with HGPS or LGPS hens (P > 0.05). However, different regulations of DA and adrenal function were found between HGPS and LGPS hens when paired with DXL hens. Compared to HGPS hens, LGPS hens had greater levels of DA and CORT (P < 0.01 and P < 0.05, respectively). In addition, under the HGPS-LGPS social treatment, the concentrations of DA but not CORT were greater in LGPS hens than in HGPS hens (P < 0.05 and P > 0.05, respectively). The results indicated genetic selection for production and survivability differentially altered DA and CORT systems in response to social stress. The data suggested, compared to LGPS hens, HGPS hens had a better coping capability to social stress, which might have been responsible for their higher productivity and survivability.

Relationships between leg disorders and changes in the behaviour of broiler chickens.

The relationships between the severity of lameness, the presence of tibial dyschondroplasia, and the frequency of dustbathing behaviour and duration of tonic immobility were studied in 96 broiler chicks kept from day-old in groups of four in wire-floored cages. Dustbathing was observed when the birds were given access for one hour to a tray containing sand or straw. The duration of tonic immobility and the severity of lameness were scored during weeks 3, 4, 5 and 6. After slaughter at 41 or 45 days of age the birds were examined for tibial dyschondroplasia; 34 birds were classified as having tibial dyschondroplasia and 54 had detectable lameness problems. Birds with tibial dyschondroplasia had a higher lameness score (P < 0.001), dustbathed on fewer days (P < 0.0001), and had longer periods of tonic immobility (P < 0.03) at six weeks than birds which did not have the condition. However, almost all the chicks, including those with tibial dyschondroplasia dustbathed on day 27 after they had not been given access to the tray for three days, significantly more than on days when they had not been deprived of the tray (P < 0.0001). Furthermore, lame birds and birds with tibial dyschondroplasia also dustbathed less with age. Studies of the vertical wing-shaking element of dustbathing confirmed that tibial dyschondroplasia reduced dustbathing (P < 0.05) and also showed that during the one-hour tests, sand resulted in more dustbathing than straw (P < 0.01).

Aggressive pecking by males in breeding groups of Japanese quail (Coturnix japonica).

1. Head injuries caused by aggressive pecking are an important welfare problem in quail farming. The aim of experiments one to three was to reduce the rate of aggressive pecking in breeder groups. 2. The quails were housed in pens containing litter, nest boxes and a dustbathing box. The experimental groups consisted of 2/14, 3/14, 5/15 or 5/35 (males/hens) quails which were introduced into the experimental pens at the age of 4, 6 or 7 weeks. 3. None of the 5 factors that varied between the pens (visual barriers, age of introduction into the pens, number of hens per 5 males, number of males per 14 hens and light intensity) had a significant effect on the rate of aggressive pecking interactions between males. 4. Because of serious head injuries 20%, 17.5% and 12.5% (experiments 1, 2, 3) of the males had to be removed from their groups. 5. In single-male groups containing 8, 12, 16 and 20 hens (experiment 4) the percentages of fertilised eggs were 92%, 84%, 77% and 69% (medians, n = 4 pens per group size). No males were seriously injured in these groups. 6. It is concluded that for welfare reasons multi-male breeding groups of Japanese quail cannot be recommended. Given the satisfactory fertility observed in groups with a sex ratio of 1:8 or 1:12, single-male groups are also of interest for economic reasons: food costs are reduced.