Free-range Chicken Meat Research Articles

Investigation of Campylobacter colonization in three Australian commercial free-range broiler farms

Campylobacter spp. contaminated poultry products are strongly associated with foodborne illnesses worldwide. Development of effective management strategies to reduce contamination by Campylobacter spp. requires an improved understanding of the numerous factors that drive these contamination processes. Currently, chicken farms are using more free-range chicken meat production systems in response to consumer preferences. However, Campylobacter spp. colonization has rarely been investigated on free-range broiler farms. The present study investigated the temporal and environmental factors influencing Campylobacter spp. colonization of free-range broilers as well as potential sources and genetic diversity of Campylobacter jejuni (C. jejuni) and Campylobacter coli (C. coli) in commercial free-range broiler farms. Genetic linkages among the isolates were analyzed using flaA amplicon analysis. Campylobacter coli was first detected in fecal samples of a commercial free-range broiler flock on day 10 of rearing. Multiple genotypes of C. jejuni and C. coli were identified in this study. The farm environment was identified as a potential source of C. jejuni and C. coli colonization of free-range broilers. The dominant Campylobacter genotype varied between free-range broiler farms over time, with C. jejuni being the most frequently isolated species. These findings enhance the understanding of C. jejuni and C. coli colonization in free-range broiler farms and could inform the development of more effective intervention strategies to help control this important foodborne pathogen.

Optimization of sustainability, selling price, and minimum cost transportation in supply chain management of free-range meat chicken in Pasuruan Regency, Indonesia

The purpose of the study was to analyze the sustainability of supply of free-range meat chicken in Pasuruan Regency, Indonesia and to obtain an optimization model of selling price and transportation costs of the free-range meat chicken. Artificial neural networks was used to analyse the sustainability of free-range meat chicken supply while linear programming was used to optimize the selling price. In addition, Vogel’s approximation was used to obtain the minimum total cost of transportation. The outcome of the analysis showed that the availability of free-range meat chicken in 2022 was estimated around 40, 016.67 tons with a selling price of IDR 28,100/kg. The minimum overall transportation cost was IDR 3,807,000/quintal.

Using genomics to understand inter- and intra- outbreak diversity of Pasteurella multocida isolates associated with fowl cholera in meat chickens.

Fowl cholera, caused by Pasteurella multocida, continues to be a challenge in meat-chicken-breeder operations and has emerged as a problem for free-range meat chickens. Here, using whole-genome sequencing (WGS) and phylogenomic analysis, we investigate isolate relatedness during outbreaks of fowl cholera on a free-range meat chicken farm over a 5-year period. Our genomic analysis revealed that while all outbreak isolates were sequence type (ST) 20, they could be separated into two distinct clades (clade 1 and clade 2) consistent with difference in their lipopolysaccharide (LPS) type. The isolates from the earlier outbreaks (clade 1) were carrying LPS type L3 while those from the more recent outbreaks (clade 2) were LPS type L1. Additionally, WGS data indicated high inter- and intra-chicken genetic diversity during a single outbreak. Furthermore, we demonstrate that while a killed autogenous vaccine carrying LPS type L3 had been successful in protecting against challenge from L3 isolates it might have driven the emergence of the closely related clade 2, against which the vaccine was ineffective. The genomic results also revealed a 14 bp deletion in the galactosyltransferase gene gatG in LPS type L3 isolates, which would result in producing a semi-truncated LPS in those isolates. In conclusion, our study clearly demonstrates the advantages of genomic analysis over the conventional PCR-based approaches in providing clear insights in terms of linkage of isolate within and between outbreaks. More importantly, it provides more detailed information than the multiplex PCR on the possible structure of outer LPS, which is very important in the case of strain selection for killed autogenous vaccines.

Decreasing prevalence of contamination with extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E) in retail chicken meat in the Netherlands.

Retail chicken meat is a potential source of extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-E). In the past decade, vast national efforts were undertaken to decrease the antibiotic use in the veterinary sector, resulting in a 58% decrease in antibiotic sales in the sector between 2009 and 2014. This decrease in antibiotic use was followed by a decrease in ESBL-E prevalence in broilers. The current study investigates the prevalence of contamination with ESBL-E in retail chicken meat purchased in the Netherlands between December 2013 and August 2015. It looks at associations between the prevalence of contamination with ESBL-E and sample characteristics such as method of farming (free-range or conventional), supermarket chain of purchase and year of purchase. In the current study, 352 chicken meat samples were investigated for the presence of ESBL-E using selective culture methods. Six samples were excluded due to missing isolates or problems obtaining a good quality sequence leaving 346 samples for further analyses. Of these 346 samples, 188 (54.3%) were positive for ESBL-E, yielding 216 ESBL-E isolates (Escherichia coli (n = 204), Klebsiella pneumoniae (n = 11) and Escherichia fergusonii (n = 1)). All ESBL-E isolates were analysed using whole-genome sequencing. The prevalence of contamination with ESBL-E in retail chicken meat decreased from 68.3% in 2014 to 44.6% in 2015, absolute risk difference 23.7% (95% confidence interval (CI): 12.6% - 34.1%). The ESBL-E prevalence was lower in free-range chicken meat (36.4%) compared with conventional chicken meat (61.5%), absolute risk difference 25.2% (95% CI: 12.9% - 36.5%). The prevalence of contamination with ESBL-E varied between supermarket chains, the highest prevalence of contamination was found in supermarket chain 4 (76.5%) and the lowest in supermarket chain 1 (37.8%). Pairwise isolate comparisons using whole-genome multilocus sequence typing (wgMLST) showed that clustering of isolates occurs more frequently within supermarket chains than between supermarket chains. In conclusion, the prevalence of contamination with ESBL-E in retail chicken in the Netherlands decreased over time; nevertheless, it remains substantial and as such a potential source for ESBL-E in humans.

PCDDs, PCDFs and PCBs in locally produced foods as health risk factors in Silesia Province, Poland

Dioxins (PCDDs), furans (PCDFs) and polychlorinated biphenyls (PCBs) emitted into the environment can accumulate in foods and become a significant source of dietary exposure for consumers of these compounds. This study aims to assess the dietary exposure of the residents in a rural area of the Silesia region in southern Poland to PCDDs, PCDFs and PCBs. The goal is to estimate cancer and non-cancer health risks due to the consumption of foods of animal origin. The area has relatively higher concentration of PCDDs, PCDFs and PCBs in the air in comparison to large industrialized cities of the Silesia province. Three popular foods of animal origin, namely free-range chicken meat, free-range chicken eggs, and cow milk produced in the farms were used. The control samples were the same foods from the local grocery stores. Two exposure scenarios were considered: Firstly that residents consumed free-range foods and secondly that the food items were purchased from stores in the study area. In the first scenario, exposure to concentrations of PCDDs, PCDFs, and dioxin-like PCBs (dl-PCBs) yielded evidence of elevated cancer and non-cancer risks. The hazard quotient (HQ) was 71.3 for non-cancer risk and 7.5 × 10−3 for cancer risk. The health risk from exposure to PCDDs, PCDFs and dl-PCBs in the second scenario was 6.9 × 10−4 and HQ = 0.8, respectively. Implementation of educational activities in the study area is needed to increase the resident's awareness of the risks associated with the emissions of chlorinated persistent organic pollutants to the environment, including aspects such as the main sources of the emission and how to avoid exposure to these compounds.

The Analysis of Factors that Affecting the Amount of Free- Range Chicken Meat’s Consumption in Langkat Regency

Chicken meat is one of the livestock commodities that can meet the protein needs of the community, but there are constraints on the price side. The price of free-range chicken meat tends to fluctuate due to production and demand imbalances and has an impact on price increases. Therefore, there needs to be control so that price increases that occur in free-range chicken meat do not jump sharply The purpose of the study was to determine the factors that influence the amount of freerange chicken meat’s consumption in Langkat Regency. The study was conducted in June - August 2018. The method that used in sampling was the proportionate stratified random sampling method and used the Slovin formula. Primary data collection was carried out by interview techniques using questionnaires to respondents and secondary data collection was obtained from the agencies and agencies assembled and then analyzed with Multiple Linear Regression using SPSS 22 application. The results showed the amount of free-range chicken meat’s consumption in Langkat Regency was influenced partially by income and the number of family members with R² = 0.61.

Comparative Analysis of the Gut Microbial Composition and Meat Flavor of Two Chicken Breeds in Different Rearing Patterns

The objective of the study is to compare the effects of free-range (FR) and cage-range (CR) breeding on gut microbiota and flavor compounds of Caoke (C) and Partridge Shank chickens (Q). A total of 120 experimental chickens were assigned to FR group and CR group; each group contain both 30 Caoke chickens and 30 Partridge Shank chickens. At 154 d old, 12 chickens of each group were selected and their cecal contents were extracted and examined for the composition of gut microbiota by illumina sequencing of the V3 region of the 16S rDNA genes, and flavor compounds were analyzed through headspace-solid-phase microextraction (HS-SPME) method. The results showed that, except for acids, the amount of flavor substances in the FR group was higher than those in the CR group, especially the content of Hexanal and D-limonene. Meanwhile, the higher concentrations of carbonyls including (E,E)-2,4-decadienal, (E)-2-decenal, (E)-2-octenal, and pentanal were in the FR chicken meat, but the differences in concentrations compared with CR were not significant. High levels of ethyl hexanoate and β-ocimene were only detected in FR groups. The Firmicutes had the highest proportion of chicken cecal microbiota, whereas the Fusobacteria was only detected in the cecal samples of Q chicken in FR group. Actinobacteria was more prevalent in FR groups than in CR groups. Meanwhile, in Q chickens, the proportions of Bacteroidetes and Proteobacteria in FR group were higher than those in CR group. Using MG-RAST Subsystem Technology, we found that some genes were associated with the formation of precursors of flavor compounds or with the metabolism and degradation of aromatic compounds. Overall, CR and FR breeding influenced the gut microbiota and flavor compounds, potentially because of the changes in diet and living conditions.

Frequency of anti-Toxocara antibodies in broiler chickens in southern Brazil.

The aim of this study was to evaluate the presence of anti-Toxocara antibodies in naturally infected broiler chickens (n = 189) from the state of Paraná, southern Brazil. The chickens were reared in a semi-intensive system by small family farmers (n = 7). An enzyme-linked immunosorbent assay (ELISA) was performed to detect the presence of anti- Toxocara spp. IgY after serum adsorption with Ascaridia galli antigens. An overall seroprevalence of 67.7% (128/189; 95% CI = 61.1-74.4) was observed. The frequency of positive animals by farm ranged from 29.6% to 100%. The optical density and reactivity index values observed in ELISA test indicated the possible chronicity of infection of the evaluated chickens. Associations between the presence of antibodies and the area where the chickens were reared (p = 0.382) or the population density of dogs on the farm (p = 0.785) were not observed. This study shows a high prevalence of Toxocara spp. antibodies in broiler chickens reared in semi-intensive systems and provides evidence that chickens are a good indicator of environmental contamination by larva migrans agents. Further studies are necessary to assess the risk factors associated with poultry infection and the likelihood of toxocariasis transmission to humans via the ingestion of free-range chicken meat.

Low Pathogenic Avian Influenza Exposure Risk Assessment in Australian Commercial Chicken Farms.

This study investigated the pathways of exposure to low pathogenic avian influenza (LPAI) virus among Australian commercial chicken farms and estimated the likelihood of this exposure occurring using scenario trees and a stochastic modeling approach following the World Organization for Animal Health methodology for risk assessment. Input values for the models were sourced from scientific literature and an on-farm survey conducted during 2015 and 2016 among Australian commercial chicken farms located in New South Wales and Queensland. Outputs from the models revealed that the probability of a first LPAI virus exposure to a chicken in an Australian commercial chicken farms from one wild bird at any point in time is extremely low. A comparative assessment revealed that across the five farm types (non-free-range meat chicken, free-range meat chicken, cage layer, barn layer, and free range layer farms), free-range layer farms had the highest probability of exposure (7.5 × 10−4; 5% and 95%, 5.7 × 10−4—0.001). The results indicate that the presence of a large number of wild birds on farm is required for exposure to occur across all farm types. The median probability of direct exposure was highest in free-range farm types (5.6 × 10−4 and 1.6 × 10−4 for free-range layer and free-range meat chicken farms, respectively) and indirect exposure was highest in non-free-range farm types (2.7 × 10−4, 2.0 × 10−4, and 1.9 × 10−4 for non-free-range meat chicken, cage layer, and barn layer farms, respectively). The probability of exposure was found to be lowest in summer for all farm types. Sensitivity analysis revealed that the proportion of waterfowl among wild birds on the farm, the presence of waterfowl in the range and feed storage areas, and the prevalence of LPAI in wild birds are the most influential parameters for the probability of Australian commercial chicken farms being exposed to avian influenza (AI) virus. These results highlight the importance of ensuring good biosecurity on farms to minimize the risk of exposure to AI virus and the importance of continuous surveillance of LPAI prevalence including subtypes in wild bird populations.

Biosecurity practices on Australian commercial layer and meat chicken farms: Performance and perceptions of farmers.

This paper describes the level of adoption of biosecurity practices performed on Australian commercial chicken meat and layer farms and farmer-perceived importance of these practices. On-farm interviews were conducted on 25 free range layer farms, nine cage layer farms, nine barn layer farms, six free range meat chicken farms and 15 barn meat chicken farms in the Sydney basin bioregion and South East Queensland. There was a high level of treatment of drinking water across all farm types; town water was the most common source. In general, meat chicken farms had a higher level of adoption of biosecurity practices than layer farms. Cage layer farms had the shortest median distance between sheds (7.75m) and between sheds and waterbodies (30m). Equipment sharing between sheds was performed on 43% of free range meat chicken farms compared to 92% of free range layer farms. There was little disinfection of this shared equipment across all farm types. Footbaths and visitor recording books were used by the majority of farms for all farm types except cage layer farms (25%). Wild birds in sheds were most commonly reported in free range meat chicken farms (73%). Dogs and cats were kept across all farm types, from 56% of barn layer farms to 89% of cage layer farms, and they had access to the sheds in the majority (67%) of cage layer farms and on the range in some free range layer farms (44%). Most biosecurity practices were rated on average as ‘very important’ by farmers. A logistic regression analysis revealed that for most biosecurity practices, performing a practice was significantly associated with higher perceived farmer importance of that biosecurity practice. These findings help identify farm types and certain biosecurity practices with low adoption levels. This information can aid decision-making on efforts used to improve adoption levels.

Low- and High-Pathogenic Avian Influenza H5 and H7 Spread Risk Assessment Within and Between Australian Commercial Chicken Farms.

This study quantified and compared the probability of avian influenza (AI) spread within and between Australian commercial chicken farms via specified spread pathways using scenario tree mathematical modeling. Input values for the models were sourced from scientific literature, expert opinion, and a farm survey conducted during 2015 and 2016 on Australian commercial chicken farms located in New South Wales (NSW) and Queensland. Outputs from the models indicate that the probability of no establishment of infection in a shed is the most likely end-point after exposure and infection of low-pathogenic avian influenza (LPAI) in one chicken for all farm types (non-free range meat chicken, free range meat chicken, cage layer, barn layer, and free range layer farms). If LPAI infection is established in a shed, LPAI is more likely to spread to other sheds and beyond the index farm due to a relatively low probability of detection and reporting during LPAI infection compared to high-pathogenic avian influenza (HPAI) infection. Among farm types, the median probability for HPAI spread between sheds and between farms is higher for layer farms (0.0019, 0.0016, and 0.0031 for cage, barn, and free range layer, respectively) than meat chicken farms (0.00025 and 0.00043 for barn and free range meat chicken, respectively) due to a higher probability of mutation in layer birds, which relates to their longer production cycle. The pathway of LPAI spread between sheds with the highest average median probability was spread via equipment (0.015; 5–95%, 0.0058–0.036) and for HPAI spread between farms, the pathway with the highest average median probability was spread via egg trays (3.70 × 10−5; 5–95%, 1.47 × 10−6–0.00034). As the spread model did not explicitly consider volume and frequency of the spread pathways, these results provide a comparison of spread probabilities per pathway. These findings highlight the importance of performing biosecurity practices to limit spread of the AI virus. The models can be updated as new information on the mechanisms of the AI virus and on the volume and frequency of movements shed-to-shed and of movements between commercial chicken farms becomes available.

Faktor- Faktor yang Mempengaruhi Permintaan Daging Ayam Kampung di Pasar Tradisional Kota Surakarta

This research aimed to find out the factors affecting the demand for free-range chicken meat among consumers and to find out the difference of demand between one consumer group and another by demographic characteristics of consumers in traditional markets of Surakarta City. This research was conducted from August 24 to September 21, 2017 in traditional markets of Surakarta City using survey method. This study was a descriptive and associative research. Respondents were 60 (sixty) buyers of free-range chicken meat selected using convenience sampling method. The data obtained consisted of primary and secondary ones. Primary data included demographic characteristics (income, age, education, and family member number), free-range chicken meat price, and broiler chicken meat price. Secondary data included data from Animal Husbandry Service, Central Statistic Bureau, and literature. Data analysis was carried out using a multiple linear regression analysis, followed with determinacy test (R 2 ), F test, t-test and One-way Anova test. From the multiple linear regression analysis, the following equation was obtained = Y = 4.811 – 2.443X 1 - 4.366X 2 - 0.038X 3 + 5.503X 4 - 0.248X 5 - 0.197X 6 + 1.518. R 2 value was 0.593, meaning that all independent variables affected dependent variable (demand for free-range chicken meat) by 59.3%. The result of Ftest showed F statistic 12.876 > F table 2.275, meaning that H 0 was not supported, indicating that independent variables affected simultaneously the dependent one. The result of t test and One-way Anova test showed that age and income partially (individually) affected significantly the demand for free-range chicken meat. The conclusion of research was that all variables affected simultaneously the demand for free-range chicken meat, and age and income factors individually showed the difference of demand for free-range chicken meat in traditional market of Surakarta City.

Correction: Comparisons of management practices and farm design on Australian commercial layer and meat chicken farms: Cage, barn and free range.

[This corrects the article DOI: 10.1371/journal.pone.0188505.].

Wildlife Presence and Interactions with Chickens on Australian Commercial Chicken Farms Assessed by Camera Traps.

The types of wildlife and the frequency of their visits to commercial chicken farms in Australia were assessed using infrared and motion-sensing camera traps. Cameras were set up on 14 free-range layer farms, three cage layer farms, two barn layer farms, five non-free-range meat chicken farms, and six free-range meat chicken farms in the Sydney basin region and South East Queensland. Wildlife visits were found on every farm type and were most frequent on cage layer farms (73%), followed by free-range layer farms (15%). The common mynah ( Acridotheres tristis) was the most frequent wildlife visitor in the study (23.9%), followed by corvids (22.9%) and Columbiformes (7.5%). Most wildlife visits occurred during the day from 6 am to 6 pm (85%). There were infrequent observations of direct contact between chickens and wildlife, suggesting the indirect route of pathogen transfer may be more significant. The level of biosecurity on the farm is suggested to impact the frequency of wildlife visits more so than the farm type.

Concentrations and human health risk assessment of DDT and its metabolites in free-range and commercial chicken products from KwaZulu-Natal, South Africa

ABSTRACTOrganochlorine pesticides such as dichlorodiphenyltrichloroethane (DDT) have been used in agriculture and for disease control purposes over many decades. Reports suggest that DDT exposure may result in a number of adverse effects in humans. In the KwaZulu-Natal Province of South Africa, DDT is sprayed annually in homes (indoor residual spraying) to control the mosquito vector of malaria. In the northern part of the Province, samples of free-range chicken meat (n = 48) and eggs (n = 13), and commercially produced chicken meat (n = 6) and eggs (n = 11), were collected and analysed. Of the free-range chicken meat samples, 94% (45/48) contained DDTs (ΣDDTs median 6.1 ng/g wet weight [ww], maximum 79.1 ng/g ww). Chicken egg contents were also contaminated (ΣDDTs in free-range eggs median 9544 ng/g ww, maximum 96.666 ng/g ww; and in commercial eggs median 1.3 ng/g ww, maximum 4.6 ng/g ww). The predominant DDT congener detected was p,pʹ-DDE in both free-range meat (>63%) and eggs (>66%), followed by p,pʹ-DDT and then p,pʹ-DDD. Based on estimated daily intake values, calculated human risk ratio (carcinogenic) values were >1 for DDTs detected in both free-range chicken products. Consumption of free-range eggs poses a particularly high health risk.

Prevalence and antimicrobial profile of Campylobacter isolates from free-range and conventional farming chicken meat during a 6-year survey

The present study aimed to investigate the prevalence of Campylobacter spp. in the meat of free-range and conventional farming broilers and to assess the respective antimicrobial susceptibility of the isolates. Three hundred and sixty nine fresh chicken meat samples were collected from different farms at slaughter (60 from free-range poultry farms and 309 from conventional farms) in North Western Greece. Susceptibility tests against 12 antimicrobials (amikacin, gentamicin, imipenem, cefamandole, cefotaxime, cefoxitin, imipenem, erythromycin, ampicillin, amoxicillin – clavulanic acid, ciprofloxacin, tetracycline) were performed. Campylobacter spp. was isolated from 91 (29.4%) of the free-range chicken meat and from 106 (28.7%) of the conventional farming chicken meat samples. The annual incidence of Campylobacter spp. among the free-range and conventional broilers was not statistically significant. However, a reducing trend was observed in the overall prevalence of Campylobacter spp. from 2005 to 2010. Variable resistance rates were observed towards the tested antimicrobials: erythromycin (76%), tetracyclines (71%), ampicillin (66%), ciprofloxacin (51%), cefamendole (41%) cefoxitin (27%), amikacin (15%), and cefotaxime (5%). No differences were observed in the antimicrobial susceptibility of isolates from free-range and conventional farming samples.

Environmental health risk assessment of dioxin in foods at the two most severe dioxin hot spots in Vietnam.

Bien Hoa and Da Nang airbases were bulk storages for Agent Orange during the Vietnam War and currently are the two most severe dioxin hot spots. This study assesses the health risk of exposure to dioxin through foods for local residents living in seven wards surrounding these airbases. This study follows the Australian Environmental Health Risk Assessment Framework to assess the health risk of exposure to dioxin in foods. Forty-six pooled samples of commonly consumed local foods were collected and analyzed for dioxin/furans. A food frequency and Knowledge-Attitude-Practice survey was also undertaken at 1000 local households, various stakeholders were involved and related publications were reviewed. Total dioxin/furan concentrations in samples of local "high-risk" foods (e.g. free range chicken meat and eggs, ducks, freshwater fish, snail and beef) ranged from 3.8 pg TEQ/g to 95 pg TEQ/g, while in "low-risk" foods (e.g. caged chicken meat and eggs, seafoods, pork, leafy vegetables, fruits, and rice) concentrations ranged from 0.03 pg TEQ/g to 6.1 pg TEQ/g. Estimated daily intake of dioxin if people who did not consume local high risk foods ranged from 3.2 pg TEQ/kg bw/day to 6.2 pg TEQ/kg bw/day (Bien Hoa) and from 1.2 pg TEQ/kg bw/day to 4.3 pg TEQ/kg bw/day (Da Nang). Consumption of local high risk foods resulted in extremely high dioxin daily intakes (60.4-102.8 pg TEQ/kg bw/day in Bien Hoa; 27.0-148.0 pg TEQ/kg bw/day in Da Nang). Consumption of local "high-risk" foods increases dioxin daily intakes far above the WHO recommended TDI (1-4 pg TEQ/kg bw/day). Practicing appropriate preventive measures is necessary to significantly reduce exposure and health risk.

Effects of panels and perches on the behaviour of commercial slow-growing free-range meat chickens

Environmental enrichment has the potential to benefit the welfare of farm animals. In poultry, panels and perches are two of the most commonly used forms of enrichment but few studies have determined their effects under commercial conditions. The aim of this work was to assess the impact of these forms of enrichment on the behaviour of slow-growth free range meat chickens. The study was conducted in four commercial farms each with 3900 birds, housed in three independent houses with access to an outdoor area. One house in each farm was outfitted with indoor and outdoor panels, the second with perches, and the third house was used as a control and had no enrichment. In each house 40 birds were tagged for individual recognition. Focal observations were performed from 6 to 12 weeks of age, with thirty 5min focal samples collected in each house in the indoor and outdoor areas alternatively. In addition, the location (in XY coordinates) of tagged birds inside and out, and their behaviour, was also collected. We did not find a main effect of treatment on the behaviour inside or outside the house (P>0.05). However, the interaction between treatment and week of age for standing (P<0.05) indicated a general increase with week of age only for the perch treatment inside the houses, and for only the perch and control treatments in the outdoor area (P<0.05). Resting decreased until week 9, while locomotive behaviours increased until week of age 10 in the outdoor area (P<0.05), with both trends reversing afterwards. A higher percentage of birds performed locomotive behaviours more often in the central area of the house in the panel treatment as compared to the control (P<0.05), with perch treatment showing intermediate values. Overall, environmental complexity had a limited effect on the behaviour of slow-growth meat chickens, although the perch presence translated into a higher percentage of standing. It is likely that the reduced effects of the environmental enrichment treatments would have been greater if more devices were introduced.

Prevalence of Antimicrobial Resistance in Enterococci and Escherichia coli in Meat Chicken Flocks During a Production Cycle and Egg Layer Pullets During Rearing

Avian Pathogenic Escherichia coli (APEC) and some enterococci are important zoonotic pathogens associated with poultry and some human illnesses. This study was conducted to evaluate the phenotypic antibiotic resistance and resistance genes during the production cycle of healthy free-range meat chickens and egg layer pullets raised in two different controlled farms in South Australia, in particular to determine at which point in the production cycle birds become colonized with antibiotic resistant bacteria. Antibiotic resistance was investigated in faecal E. coli (206) and enterococcal (252) isolates by agar dilution and polymerase chain reaction. Southern hybridization was carried on plasmids from selected multi-resistant E. coli isolates to determine the location of resistance genes. Our results revealed that birds are colonized with resistant bacteria encoding various resistance genes from a very early age. Resistance to ampicillin and tetracycline (and associated resistance genes) were the most frequently detected resistances in E. coli isolates from egg layer pullets and free-range meat chickens. Phenotypically resistant enterococcal isolates from 3-5 days old chickens carried genetic determinants for resistance to tetracycline, bacitracin and tylosin. Whilst statistical analysis revealed there was no significant differences (p<0.05) with the phenotypic resistance observed in the E. coli and enterococcal isolates from meat chickens and egg layer pullets, a significant difference was observed in resistant E. coli isolates containing blaTEM and tet genes. This study demonstrates that newly hatched chicks are already colonized with resistant bacteria which persist through the production cycle and can potentially contaminate eggs and chicken carcasses. This study also confirms that poultry are a potential source of pathogenic E. coli strains.

Free-choice feeding of free-range meat chickens

SUMMARY Interest in small- and medium-scale free-range poultry production for local and regional markets is growing, and alternative feeding methods should be considered. Free-choice feeding is a method that offers birds separate feedstuffs, such as grains, protein concentrates, and natural vitamin and mineral sources, from which they can self-select a diet suited to their changing needs. Free-choice feeding may prove useful in production systems with outdoor access because nutrient needs change widely due to temperature fluctuations and bird activity. Many small producers do not have access to the nutritional services that large producers do and may have specific goals in regard to nutrition, such as using farm-raised feed ingredients and pasture forage to provide nutrients. In addition, most organic programs do not permit the use of synthetic amino acids in feed. Free-choice methods have been used historically and can be useful for alternative producers, making use of farm-raised feeds to improve savings and increase nutrient cycling. In the current study, a fully formulated diet and free-choice diet were compared in a free-range system using slow-growing meat chickens. The formulated diet was a commercial product (20% CP), whereas the free-choice diet chosen by birds was much lower in CP (13%). Final live weights did not differ between treatments; however, ready-to-cook yield and breast yields were higher in the birds from the formulated treatment, most likely due to amino acid supplements in the formulated feed. The diet chosen by free-choice birds was less expensive than the formulated diet.