Backyard Flocks Research Articles

A molecular survey of Eimeria in chickens across Australia

Coccidiosis is a costly enteric disease of chickens caused by protozoan parasites of the genus Eimeria. Disease diagnosis and management is complicated since there are multiple Eimeria species infecting chickens and mixed species infections are common. Current control measures are only partially effective and this, combined with concerns over vaccine efficacy and increasing drug resistance, demonstrates a need for improved coccidiosis diagnosis and control. Before improvements can be made, it is important to understand the species commonly infecting poultry flocks in both backyard and commercial enterprises. The aim of this project was to conduct a survey and assessment of poultry Eimeria across Australia using genetic markers, and create a collection of isolates for each Eimeria species. A total of 260 samples (faecal or caecal) was obtained, and survey results showed that Eimeria taxa were present in 98% of commercial and 81% of backyard flocks. The distribution of each Eimeria species was widespread across Australia, with representatives of all species being found in every state and territory, and the Eimeria species predominating in commercial flocks differed from those in backyard flocks. Three operational taxonomic units also occurred frequently in commercial flocks highlighting the need to understand the impact of these uncharacterised species on poultry production. As Eimeria infections were also frequent in backyard flocks, there is a potential for backyard flocks to act as reservoirs for disease, especially as the industry moves towards free range production systems. This Eimeria collection will be an important genetic resource which is the crucial first step in the development of more sophisticated diagnostic tools and the development of new live vaccines which ultimately will provide savings to the industry in terms of more efficient coccidiosis management.

Sero-surveillance and risk factors for avian influenza and Newcastle disease virus in backyard poultry in Oman

Avian Influenza (AI) and Newcastle disease (ND) are the most important reportable poultry diseases worldwide. Low pathogenic AI (H9N2) and ND viruses are known to have been circulating in the Middle East, including in Oman, for many decades. However, detailed information on the occurrence of these pathogens is almost completely lacking in Oman. As backyard poultry are not vaccinated against either virus in Oman, this sector is likely to be the most affected poultry production sector for both diseases. Here, in the first survey of AI and ND viruses in backyard poultry in Oman, we report high flock-level seroprevalences of both viruses. Serum and oropharyngeal swabs were taken from 2350 birds in 243 backyard flocks from all regions and governorates of Oman. Information was recorded on location, type of bird and housing type for each sampled farm. Individual bird serum samples were tested using commercial indirect antibody detection ELISA kits. Pooled oropharyngeal samples from each flock were inoculated onto FTA cards and tested by RT-PCR. Samples came from chickens (90.5%), turkeys (2.1%), ducks (6.2%), guinea fowl (0.8%) and geese (0.4%). The bird-level seroprevalence of antibody to AI and ND viruses was 37.5% and 42.1% respectively, and at the flock level it was 84% and 90% respectively. There were statistically significant differences between some different regions of Oman in the seroprevalence of both viruses. Flock-level NDV seropositivity in chickens was significantly associated with AIV seropositivity, and marginally negatively associated with flock size. AIV seropositivity in chickens was marginally negatively associated with altitude. All oropharyngeal samples were negative for both viruses by RT-PCR, consistent with a short duration of infection. This study demonstrates that eight or nine out of ten backyard poultry flocks in Oman are exposed to AI and ND viruses, and may present a risk for infection for the commercial poultry sector in Oman, or wild birds which could carry infection further afield.

Screening for Salmonella in backyard chickens

Salmonellosis is a significant zoonotic disease which has a considerable economic impact on the egg layer industry. There is limited information about the prevalence of Salmonella spp. in backyard chickens. The current study was conducted to determine the prevalence of Salmonella in backyard chickens, and the associated virulence of any serovars identified. Hundred and fifteen pooled samples from 30 backyard flocks in South Australia were screened. Four flocks tested positive for Salmonella spp. The overall Salmonella isolation rate in the current study was 10.4%. The estimated prevalence at individual bird level was 0.02% (95% CI 0.025–0.975). The serovars isolated were Salmonella Agona, Salmonella subsp 2 ser 21:z10:z6 (Wandsbek) and Salmonella Bovismorbificans. All Salmonella isolates tested positive for the prgH, orfL and spiC genes. The Salmonella subsp 2 ser 21:z10:z6 (Wandsbek) had the most antibiotic resistance, being resistant to ampicillin and cephalothin and having intermediate resistance to florphenicol. All of the Salmonella Agona had intermediate resistance to the ampicillin, while the Salmonella Bovismorbificans were susceptible to all antibiotics tested. With the increased interest of keeping backyard chickens, the current study highlights the zoonotic risk from Salmonella spp. associated with home flocks.

Questionnaire study and postmortem findings in backyard chicken flocks in Finland.

BackgroundAlthough modern commercial poultry production today is based on large farms and intensive husbandry, keeping backyard poultry has regained popularity in industrialized countries. However, the health status of backyard flocks is still relatively poorly documented. A questionnaire was sent to the owners of 376 backyard poultry flocks (<500 birds) in order to study health management procedures and characterize backyard poultry populations in Finland. Information was also collected on the postmortem findings from non-commercial flocks using necropsy data from the Finnish Food Safety Authority (Evira).ResultsBackyard flocks in Finland are small in size (<50 birds), comprising mainly chickens. Based on the results of the questionnaire, the health of such flocks is good, mortality low and vaccinations are not commonly used. Most of the flocks were registered in the national poultry register. The standard biosecurity practices are not generally applied and contact with wild birds, pets and farm animals is frequent, which can make the flocks more prone to infectious diseases. We conducted an 11-year retrospective study of the postmortem necropsy findings of the Evira in order to document the diseases, which caused mortality in backyard chickens in Finland. Necropsy was performed on a total of 132 non-commercial laying hens during 2000 – 2011. The most common postmortem findings were Marek’s disease (27%) and colibacillosis (17%).ConclusionsThis study is the first to report data on characteristics of and management practices for backyard chicken flocks in Finland. Close connections with commercial flocks are rare and farms are usually distantly located suggesting that the risk that these backyard flocks pose to commercial poultry is low.

Molecular detection of infectious bronchitis and avian metapneumoviruses in Oman backyard poultry

Infectious bronchitis virus (IBV) and avian metapneumovirus (aMPV) are economically important viral pathogens infecting chickens globally. Identification of endemic IBV and aMPV strains promotes better control of both diseases and prevents production losses. Orophrayngeal swab samples were taken from 2317 birds within 243 different backyard flocks in Oman. Swabs from each flock were examined by RT-PCR using part-S1 and G gene primers for IBV and aMPV respectively. Thirty-nine chicken flocks were positive for IBV. Thirty two of these were genotyped and they were closely related to 793/B, M41, D274, IS/1494/06 and IS/885/00. 793/B-like IBV was also found in one turkey and one duck flock. Five flocks were positive for aMPV subtype B. Though no disease was witnessed at the time of sampling, identified viruses including variant IBV strains, may still pose a threat for both backyard and commercial poultry in Oman.

Avian influenza surveillance in Central and West Africa, 2010-2014.

Avian influenza virus (AIV) is an important zoonotic pathogen, resulting in global human morbidity and mortality and substantial economic losses to the poultry industry. Poultry and wild birds have transmitted AIV to humans, most frequently subtypes H5 and H7, but also different strains and subtypes of H6, H9, and H10. Determining which birds are AIV reservoirs can help identify human populations that have a high risk of infection with these viruses due to occupational or recreational exposure to the reservoir species. To assess the prevalence of AIV in tropical birds, from 2010 to 2014, we sampled 40099 birds at 32 sites in Central Africa (Cameroon, Central African Republic, Congo-Brazzaville, Gabon) and West Africa (Benin, Côte d'Ivoire, Togo). In Central Africa, detection rates by real-time RT-PCR were 16·6% in songbirds (eight passerine families, n=1257), 16·4% in kingfishers (family Alcedinidae, n=73), 8·2% in ducks (family Anatidae, n=564), and 3·65% in chickens (family Phasianidae, n=1042). Public health authorities should educate human cohorts that have high exposure to these bird populations about AIV and assess their adherence to biosecurity practices, including Cameroonian farmers who raise small backyard flocks.

High seroprevalence of respiratory pathogens in hobby poultry.

Seroprevalence studies on respiratory pathogens have been done extensively in commercial laying hens, broilers, and, to a lesser extent, backyard poultry. In Europe, seroprevalence studies in backyard and fancy breed poultry flocks are scarce and limited to a few pathogens, such as Mycoplasma gallisepticum (MG); others, such as Ornithobacterium rhinotracheale (ORT), are missing. A commercial ELISA for detection of antibodies against six selected pathogens was performed on 460 serum samples from chickens across Flanders. Anti-ORT antibodies were, by far, the most prevalent, with a prevalence of 95.4%. Infectious bronchitis virus, Mycoplasma synoviae, and avian metapneumovirus antibodies were found in 75.6%, 76.3%, and 63.5% of the animals, respectively. Antibodies against MG and infectious laryngotracheitis virus were found in 36.7% and 30% of the animals, respectively. These data demonstrate the high seroprevalence of respiratory pathogens among hobby poultry; therefore, it is possible that this group could act as a reservoir for commercially kept poultry.

Backyard chickens in the United States: A survey of flock owners

Although it has become increasingly popular to keep backyard chickens in the United States, few studies have provided information about these flocks. An online survey of backyard chicken owners was conducted, advertised through Master Gardeners’ websites, social platforms, and other sites. The survey had 56 questions about flock history, husbandry, health care, and owner attitudes and demographics. Surveys received (n = 1,487) came almost equally from urban, suburban, and rural areas. Most (71%) respondents owned fewer than 10 chickens and had kept chickens for less than 5 yr (70%). Major reasons for keeping chickens were as food for home use (95%), gardening partners (63%), pets (57%), or a combination of these. Rural respondents had larger flocks (P ≤ 0.001) and were more likely to keep chickens as a source of income or for show (P ≤ 0.001) than urban and suburban respondents. Owners thought that eggs/meat from their chickens were more nutritious (86%), safer to consume (84%), and tasted better (95%) than store-bought products, and also that the health and welfare of their chickens was better (95%) than on commercial farms. The majority (59%) indicated no flock health problems in the last 12 mo. However, there was a lack of awareness about some poultry health conditions. Many knew either little or nothing about exotic Newcastle or Marek's disease, and most (61%) did not vaccinate against Marek's. Respondents wanted to learn more about various flock management topics, especially how to detect (64%) and treat (66%) health problems. The Internet was the main source of information (87%) used by backyard flock owners, followed by books/magazines (62%) and feed stores (40%). Minimizing predation was the most cited challenge (49%), followed by providing adequate feed at low cost (28%), dealing with soil management (25%), and complying with zoning regulations (23%). The evidence obtained from this survey will help to determine what information and resources are needed to maintain good biosecurity and improve the health and welfare of backyard flocks.

Antibody response and risk factors for seropositivity in backyard poultry following mass vaccination against highly pathogenic avian influenza and Newcastle disease in Indonesia.

A large-scale mass vaccination campaign was carried out in Java, Indonesia in an attempt to control outbreaks of highly pathogenic avian influenza (HPAI) in backyard flocks and commercial smallholder poultry. Sero-monitoring was conducted in mass vaccination and control areas to assess the proportion of the target population with antibodies against HPAI and Newcastle disease (ND). There were four rounds of vaccination, and samples were collected after each round resulting in a total of 27 293 samples. Sampling was performed irrespective of vaccination status. In the mass vaccination areas, 20-45% of poultry sampled had a positive titre to H5 after each round of vaccination, compared to 2-3% in the control group. In the HPAI + ND vaccination group, 12-25% of the population had positive ND titres, compared to 5-13% in the areas without ND vaccination. The level of seropositivity varied by district, age of the bird, and species (ducks vs. chickens).

Targeted survey of Newcastle disease virus in backyard poultry flocks located in wintering site for migratory birds from Southern Brazil

Newcastle disease virus (NDV) causes a fast-spreading, highly contagious infectious disease in several bird species. Commercial poultry farms in Brazil were considered free of virulent NDV. Data on NDV infection levels in backyard poultry flocks and the epidemiology of the disease are limited. The aim of this study was to perform a NDV survey in backyard poultry from households flocks located around one of the main wintering sites for migratory wild birds in Brazil, and to identify potential risk factors associated with NDV. Backyard poultry may be sentinels and a source of infection for commercial poultry, since they may have as much contact with these birds as with migratory wild birds. Data were collected from 48 randomly selected households using an epidemiological questionnaire. Serum samples from poultry were tested for NDV antibodies using an ELISA, and tracheal and cloacal swabs were collected for NDV molecular detection. The risk factors were assessed using a multivariate Poisson regression with robust variance. The ELISA showed that 33.8% of the serum samples were positive for anti-NDV antibodies and in 42 households (87.5%) at least one NDV-positive bird was found. Tracheal and cloacal swabs were negative for NDV by real time RT-PCR, possible because within this region there might flow a low pathogenicity NDV strain, which can induce seroconversion with innaparent clinical findings. The prevalence ratio (PR) increased when farmers used their own replacement poultry to restock their flock (PR=1.64; 95% CI: 1.11–2.42). Furthermore, the increasing distance of the household flock from the “Laguna do Peixe” estuary was associated with decreasing NDV seropositivity (PR=0.94; 95% CI: 0.90–0.99). This is the first study in Brazil evaluating the presence of NDV and the associated risk factors in households with backyard poultry flocks. The great number of farms with seropositive birds indicates that the virus circulates in backyard flocks, and this breeding system may be a source of NDV. These data can be used to establish appropriate biosecurity and husbandry measures for this type of breeding system to prevent NDV spread in Brazil.

Characterization and phylogenetic analysis of a highly pathogenic avian influenza H5N1 virus isolated from diseased ostriches (Struthio camelus) in the Kingdom of Saudi Arabia.

During 2007, two outbreaks of avian influenza virus (AIV) in backyard and commercial ostrich flocks were first reported in the Kingdom of Saudi Arabia (KSA). The infected ostriches suffered from depression, anorexia, and diarrhea and some exhibited sudden death. A rapid AIV-group antigen detection and real-time reverse-transcription PCR (rtRT-PCR) were initially performed on cloacal and tracheal swabs collected from diseased birds. Pools from positive-tested swabs for each flock were utilized for virus isolation in specific-pathogen-free embryonating chicken eggs. H5N1 AIV was identified in the harvested allantoic fluids by hemagglutination followed by hemagglutination inhibition and rtRT-PCR. The viruses responsible for these two outbreaks were sequenced and characterized as HPAIV H5N1 (A/ostrich/Saudi Arabia/6732-3/2007 and A/ostrich/Saudi Arabia/3489-73VIR08/ 2007) from backyard and commercial flocks, respectively. Phylogenetic analysis of both isolates revealed that the two viruses belong to clade 2.2 sublineage II and cluster with the HPAIV H5N1 isolated from falcons and turkeys during 2007 in KSA.

Identifying risk factors of avian infectious diseases at household level in Poyang Lake region, China

Poultry kept in backyard farms are susceptible to acquiring and spreading infectious diseases because of free ranging and poor biosecurity measures. Since some of these diseases are zoonoses, this is also a significant health concern to breeders and their families. Backyard farms are common in rural regions of China. However, there is lack of knowledge of backyard poultry in the country. To obtain first-hand information of backyard poultry and identify risk factors of avian infectious diseases, a cross-sectional study was carried out at household level in rural regions around Poyang Lake.A door-to-door survey was conducted to collect data on husbandry practices, trading practices of backyard farmers, and surrounding environments of backyard farms. Farms were categorized into cases and controls based on their history of poultry death. Data were collected for 137 farms, and the association with occurrence of poultry death event was explored by chi-square tests. Results showed that vaccination implementation was a protective factor (odds ratio OR=0.40, 95% confidence interval CI: 0.20–0.80, p=0.01), while contact with other backyard flocks increased risk (OR=1.72, 95% CI: 0.79–3.74, p=0.16). A concept of “farm connectivity” characterized by the density of particular land-use types in the vicinity of the farm was proposed to characterize the degree of contact between poultry in one household farm and those in other household farms. It was found that housing density in a 20-m buffer zone of the farmhouse was most significantly associated with poultry death occurrence (OR=1.08, 95% CI: 1.02–1.17, p=0.03), and was in agreement with observation of villagers. Binary logistic regression was applied to evaluate the relationship between poultry death event and density of land-use types in all buffer zones. When integrated with vaccination implementation for poultry, prediction accuracy of poultry death event reached 72.0%.Results combining questionnaire survey with geographical approaches indicated that occurrence of poultry death event among backyard farms within a village was heavily impacted by farm connectivity. This study provides new insight for the study and help to develop more targeted prevention and countermeasure in a typical rural environment of China.

Backyard Poultry Flocks and Salmonellosis: A Recurring, Yet Preventable Public Health Challenge

Poultry are well recognized as possible carriers of Salmonella species. As part of the local foods movement, backyard poultry flocks have increased in popularity in recent years. Between 1996 and 2012, 45 outbreaks of human Salmonella infections linked to live poultry from mail-order hatcheries were documented. This review examines the history of live poultry-associated salmonellosis in humans in the United States, the current status of the issue, and what can be done to help prevent these illnesses. An integrated One Health approach involving the mail-order hatchery industry, feed stores, healthcare providers, veterinarians, and backyard flock owners is needed to help prevent live poultry-associated salmonellosis.

Brooding on a career in avian medicine

Veterinary student Una Mcfarlane's interest in avian medicine stems from caring for her parents' backyard flock; although she is working towards a career with birds, she is not putting all her eggs in one basket just yet

Putative human and avian risk factors for avian influenza virus infections in backyard poultry in Egypt

Highly pathogenic influenza A virus subtype H5N1 causes significant poultry mortality in the six countries where it is endemic and can also infect humans. Egypt has reported the third highest number of poultry outbreaks (n=1084) globally. The objective of this cross-sectional study was to identify putative risk factors for H5N1 infections in backyard poultry in 16 villages in Damietta, El Gharbia, Fayoum, and Menofia governorates from 2010–2012. Cloacal and tracheal swabs and serum samples from domestic (n=1242) and wild birds (n=807) were tested for H5N1 via RT-PCR and hemagglutination inhibition, respectively. We measured poultry rearing practices with questionnaires (n=306 households) and contact rates among domestic and wild bird species with scan sampling. Domestic birds (chickens, ducks, and geese, n=51) in three governorates tested positive for H5N1 by PCR or serology. A regression model identified a significant correlation between H5N1 in poultry and the practice of disposing of dead poultry and poultry feces in the garbage (F=15.7, p<0.0001). In addition, contact between domestic and wild birds was more frequent in villages where we detected H5N1 in backyard flocks (F=29.5, p<0.0001).

Popular Backyard Flock program reduces biosecurity risks of amateur production

The California Animal Health and Food Safety laboratories provide free necropsy (postmortem examination) services to owners of backyard poultry through the Backyard Flock program funded by the California Department of Food and Agriculture. We collected and analyzed data on the number of poultry submissions to the program between 2007 and 2012, the lab totals by location and the diseases diagnosed. During those 6 years, submissions increased 383%, with chickens representing 91% of them, and the greatest increases occurred in Santa Clara, Los Angeles and Sonoma counties. The necropsy data showed that the digestive (32.5%) and hemolymphatic (16.9%) systems were the most commonly affected. Marek's disease accounted for 13.3% of diagnoses (492 cases). With the rapid rise in the number of poultry being raised by amateur producers, biosecurity education is essential.

Cluster randomised trial of the impact of biosecurity measures on poultry health in backyard flocks

In Cambodia, most poultry are raised in backyard flocks with a low level of biosecurity, which increases the risk of spread of infectious diseases. The aim of this study was to evaluate the effectiveness of a practical biosecurity intervention based on affordable basic measures. A cluster randomised trial was conducted in 18 villages in Cambodia from November 2009 to February 2011. Generalised estimating equations were used to test the association between the intervention and mortality rates in flocks of chickens and ducks. Mortality rates in chicken flocks in intervention villages (mean 6.3%, range 3.5–13.8%, per month) were significantly higher than in control villages (mean 4.5%, range 2.0–9.7%, per month; P<0.01). Mortality rates in duck flocks in intervention villages (mean 4.1%, range 1.9–7.9%, per month) were significantly higher than in control villages (mean 2.8%, range 0.6–8.0%, per month; P<0.01). Despite good compliance among poultry owners, the biosecurity intervention implemented in this study was not associated with improvements in poultry mortality rates. These findings suggest that basic biosecurity measures may not suffice to limit the spread of infectious diseases in backyard poultry flocks in Cambodia.

Prevalence and Differentiation of Diseases in Maryland Backyard Flocks

Several epidemiologic surveillance studies have implicated backyard flocks as a reservoir for poultry diseases; however, much debate still exists over the risk these small flocks pose. To evaluate this concern, the prevalence of Newcastle disease (ND), infectious laryngotracheitis (ILT), Mycoplasma gallisepticum (MG), and Salmonella was determined in 39 Maryland backyard flocks. Serum, tracheal, and cloacal swabs were randomly collected from 262 birds throughout nine counties in Maryland. Through PCR and ELISA analysis, disease prevalence and seroprevalence were determined in flocks, respectively, for the following: ND (0%, 23%); ILT (26%, 77%); MG (3%, 13%); and Salmonella (0%, not done). Vaccine status could not be accurately confirmed. Premise positives were further differentiated and identified by partial nucleotide sequencing. Screening of the 10 ILT premise positives showed that most were live attenuated vaccines: eight matched a tissue culture origin vaccine, one matched a chicken embryo origin (CEO) vaccine, and one was CEO related. The single MG-positive flock, also positive for the CEO-related sequence, was identified as the infectious S6 strain. The prevalence rates for these economically important poultry diseases ranged from none to relatively low, with the vast majority of sampled flocks presenting no clinical signs.

Avian Influenza Biosecurity: Filling the Gaps with Non-Traditional Education

Outbreaks of highly pathogenic avian influenza have become endemic, crippling trade and livelihood for many, and in rare cases, resulting in human fatalities. It is imperative that up-to-date education and training in accessible and interactive formats be available to key target audiences like poultry producers, backyard flock owners, and emergency responders. Online tools such as Moodle™, Second Life™, and Facebook are excellent resources for Extension educators and have been implemented in the arsenal of the avian influenza biosecurity program. However, each online tool has its pros and cons, and Extension educators must use the best tool for each target audience.

Evaluation of Maryland Backyard Flocks and Biosecurity Practices

Domesticated poultry are susceptible to infectious and zoonotic diseases and can serve as a transmission source to other bird and human populations. In recent years, the number of noncommercial poultry has been on the rise in the United States. To evaluate potential risks of this growing population, a descriptive epidemiologic survey was conducted among Maryland backyard flocks. Owner and flock demographics were characterized as well as management practices such as husbandry, human-to-bird interaction, bird exposure risks, poultry health status, and biosecurity. Data from the 41 returned questionnaires indicated a median flock size of 38 birds (range, 3-901). Chickens accounted for 86.5% of the reported birds overall. Just over half of the owners (51.2%) kept chickens only, with the remaining backyard flocks consisting of chickens, other gallinaceous species, waterfowl, or a combination. Of flocks with multiple species, 70.0% of owners did not keep them separate. Almost two thirds of owners (61.0%) had kept poultry for < or = 5 yr, with 44.0% of all flocks on free range. Over the past 2 yr, predation was the highest cause of specific mortality (57.1%) followed by disease (30.2%), unknown (8.7%), and injury (4.0%), and over half of owners (56.1%) reported signs of disease in their flock within the last 6 mo. Biosecurity practices were highly variable among flocks. Data from this study identified gaps in the disease prevention and biosecurity practices of backyard flocks. These results can be useful in developing educational extension and outreach programs as well as policies, in efforts to further mitigate the spread of diseases.