Persistence of the V4 strain of Newcastle disease virus in an open-range flock of chickens

The V4 strain of Newcastle disease virus was introduced into a small open range flock of bantam chickens, by dosing half the birds directly into the crop. As indicated by rises in titres of haemagglutination inhibition antibody, the virus spread to the uninoculated birds and persisted in the flock for two years, infecting chickens that were introduced by natural brooding and rearing. All new clutches of chicks seroconverted by 80 days of age, and the titres of adult birds showed a concurrent rise, suggesting that the chicks were amplifying the virus. The modes of spread and of persistence of the virus were not determined; although cloacal swabs were taken regularly, only one yielded virus. Antibody titres of the inoculated birds remained above the presumptive protective level of 3 (log2) for over a year, whereas the titres of birds infected by contact were generally less than 3.     

Comparative Analysis of Village Chicken Production in Two Farming Systems in Burkina Faso

This study aimed to describe and compare village chicken production in two farming systems in Burkina Faso. The systems were those in which crops and livestock production were, respectively, the most important. A rapid rural appraisal preceded a monitoring study in which data were collected fortnightly for 2 months. The study revealed that village chickens are used as sacrifices, gifts and objects of exchange for traditional medicine, or are sold for a little money under both systems. Chicken production is a free-range procedure in both farming systems, but there are differences in management. On average, the flock size was 33.5±3 birds, of which 57% were chicks. During the period of 2 months in the rainy season, the overall mortality was relatively low (8.8%±1.5) but mortality in chicks was high (31.7%). The main cause of financial loss in the village chickens was mortality, which represented up to 84% of the total exits. The hatching rate and mortality in young chicks differed significantly (p<0.05) between the two farming systems.     

Free-range Village Chickens on the Accra Plains, Ghana:Their Husbandry and Productivity

A cross-sectional[4pc] survey investigating husbandry and productivity of free-range village chickens was carried out in four administrative districts within 60km of Accra. Responses were provided by 101 men and 99 women. The mean (SD) household flock size was 28.7 (25.97) and the median was 20. The factors included in the final model investigating variance in flock size were sex of the respondent (p=0.011), administrative area (p=0.004), the numbers of members in the household (p=0.017) and the number of cattle, sheep and goats owned by the household (p=0.031). Chickens were owned by individual members of the household, but women and children were the predominant providers of care for chickens. All respondents described their chickens as scavengers that were provided with supplementary feed, and over 80% of respondents named maize as a supplementary food source. Approximately 50% of respondents claimed difficulty in providing supplementary feed, with the degree of difficulty varying between administrative areas (p<0.001). A majority of respondents (approximately 65%) claimed that their chickens laid 3–4 clutches of eggs per year. Over 70% of respondents estimated that each clutch contained 10–20 eggs, and approximately 70% of respondents estimated that 75% of the eggs hatched. Opinions on mortality varied, but 60% of men and 70% of women estimated that between 50% and 75% of both chicks and adult birds died each year. Approximately 80% of respondents named Newcastle disease as the most important health issue. The opportunities for and consequences of controlling Newcastle disease are discussed.     

Local chicken production system in Malawi: Household flock structure,dynamics, management and health

Household flocks of scavenging chickens were monitored from August 2002 to August 2003 in 27 villages in Lilongwe, Malawi. The objective was to evaluate the local chicken production system by investigating flock structure, utilization, management and constraints. Farmers and researchers jointly obtained data on household flocks. Mean flock size was 12.9, with a range of 1–61 chickens. The flock dynamics of chickens over 8 weeks old constituted 91% migrating out of flocks and 9% into the flocks. Primary functions based on flock dynamics were, in order of importance, household consumption, participation in socio-cultural ceremonies, selling, exchanging breeding stock and gifts. Of the flock exits, 43.9% were due to losses from diseases, predation and theft. Most flocks (85%) were housed in human dwelling units. Scavenging was the main source of feed. The majority (77.6%) of farmers supplemented their chickens erratically with energy-rich feeds, mostly maize bran. Most supplementation took place during the cold-dry season. Village chicken production offers diverse functional outputs but faces animal health (diseases, parasites, predation) and management (feeding) constraints, which require an integrated intervention approach at community and household level.     

An assessment of chicken husbandry including Newcastle disease control in rural areas of Chibuto,Mozambique

This paper describes the management practices of village poultry in Chibuto and the impact of the Newcastle disease vaccination program conducted between January 2005 and August 2008. A 51-question survey was conducted in 11 villages involved in the Newcastle disease vaccination program in Chibuto, Mozambique. The mean flock size was significantly higher in households that provided their chickens with feed (15.0) than chickens that only scavenged (8.7; P = 0.0001). The mean flock size was significantly higher in households with vaccinated chickens (16.9) than those with unvaccinated chickens (10.0; P = 0.0005). The average number of chicks hatched during the most recent brooding was significantly higher in households that fed their chickens (9.2) than chickens that only scavenge (6.9; P = 0.0335). The mean hatch rate was significantly higher in households with vaccinated chickens (0.8) than those with unvaccinated chickens (0.7; P = 0.0324). It was determined that unvaccinated chickens are approximately five times more at risk to die of Newcastle disease (odds ratio = 4.79). This study supported the efficacy of the I-2 Newcastle disease vaccine as shown by the increased average flock size and decreased incidence of chicken mortality due to Newcastle disease. The level of farmer involvement and ongoing commitment by community vaccinators suggest that the Chibuto vaccination program is likely to be sustainable in the medium- to long-term.     

The multiple burdens of zoonotic disease and an ecohealth approach to their assessment

Individual interviews were conducted in 137 households using semi-structured questionnaires to determine the influence of socioeconomic factors on production constraints faced by indigenous chicken producers in the rural areas of South Africa. The major constraints to village chicken production were mortality (95 % of the households) followed by feed shortage (85 %) and low chicken sales (72 %). The logistic regression model showed that households that owned imported/crossbred chickens practiced extensive production system without housing structures and did not have vaccines were more likely to experience high levels of chicken mortality. Poor and youth-headed households with no supplements and vaccines had high probability of Newcastle disease. The probability of a household to experience chicken feed shortage was lower in households that owned indigenous chickens than those that owned imported/crossbred chickens (odds ratio, 11.68; 95 % confidence interval, 1.19–27.44). Youth-headed households that had small flocks and no access to veterinary services were not likely to sell chickens. It was concluded that gender, age, wealth status, production system, chicken flock size, type of chicken breed owned, accessibility of veterinary services, availability of supplements, vaccines and shelter influence village chicken farmer’s production constraints such as feed availability, chicken mortality, prevalence of diseases and chicken sales.     

Village Poultry Production Systems in the Central Highlands of Ethiopia

Participatory rural appraisal (PRA), supported by checklists and intensive case studies on individual households, was carried out in three villages at three different altitudes in the central highlands of Ethiopia. The chicken production system in each village is described and the problems are discussed. More than 60% of the families kept chickens, and in most cases the women owned and managed the birds and controlled the cash from the sales. The production systems followed were mainly low-input and small-scale, with 7–10 mature birds per household, reared in the back yards with inadequate housing, feeding and health care. The average egg production per clutch was 15–20, with 3–4 clutches per year. The mean number of eggs set per bird was 12.9±2.2 (n = 160), depending on the size of the bird and season, and the hatching rate was 80.9%±11.1%, range 44%–100% (n = 160). Poultry meat and eggs were generally accepted and appreciated in all three villages. In addition to the small amount of cash income they provide, scavenging chickens have nutritional, cultural and social functions. The flock composition, price of poultry and poultry products, disease outbreaks and hatching of chicks were strongly affected by season. Disease was cited as the most important problem by most of the members of the community, followed by predation, lack of feed, poor housing, insufficient water and parasites. Disease periodically decimated the flocks, and consequently, about 50% of the eggs produced were incubated in order to replace the birds that had died. The major source of loss in the system was the high mortality of chicks (61%) that occurred between hatching and the end of brooding at 8 weeks of age. The system was characterized by no or few inputs and a low output level. The major input was the cost of foundation stock, but after that virtually no cost was involved. The major source of feed for the birds was from the scavenging feed resource base, which comprised table leftovers, small grain supplements and anything edible from the immediate environment.     

Variation in village chicken production systems among agro-ecological zones of Zimbabwe

The degree to which village chickens are integrated in the smallholder farming systems differs depending on the socio-economic, cultural and biological factors within each system. The objective of this study was to characterise the village chicken farming systems and identify possible threats to, and opportunities for, local chickens in the agro-ecological zones of Zimbabwe. A pre-tested questionnaire was administered to households randomly selected from five districts, Risitu (n = 97), Hurungwe (n = 56), Gutu (n = 77), Gokwe-South (n = 104) and Beitbridge (n = 37) in eco-zones I–V, respectively. Age of head of household averaged 47 years (SD = 14.3). Land holdings per household averaged 4.82 ha (SD = 3.6). Overall, 17.7 percent of the households ranked livestock as the major source of income compared to 70.8 percent who ranked crops as the main contributor. Chicken flock size averaged 16.7 (SD = 12.4), and the highest flock sizes were observed in eco-zones I and IV. Households owning cattle, goats and other livestock assigned less important ranks to chickens. Chickens were used mainly for the provision of meat and eggs whilst the use of chicken feathers and investment were uncommon practises. Results indicate that more support is necessary for village chickens in the non-cropping regions of the country.     

Free-range village chickens on the Accra Plains, Ghana: Their contribution to households

A cross-sectional survey investigating the contribution of free-range village chickens to household economies was carried out in four administrative districts within 60km of Accra. Answers were provided by 101 men and 99 women. Nearly all respondents claimed to keep chickens for meat, with a far smaller percentage claiming to keep them for egg production. Over 80% of respondents kept chickens to supplement their incomes. The proportion of the flock eaten varied between administrative areas (p=0.009 and p=0.027), although this was possibly a consequence of differences in consumption patterns between occupation of the respondent, land area cultivated and flock size. The proportion of chickens sold varied as a result of differences in flock size (p=0.013), the proportion sold increasing with number of birds in the flock. Respondents generally agreed that chickens could be sold without difficulty. A majority of chicken sales were from the farm gate, directly to consumers or traders. Sales were on demand or when the owner needed money. Money from the sale was kept by the owner of the chicken and the money was spent on personal needs. The proportion of the flock sold varied between administrative areas (p=0.025) and occupation of the respondent (p=0.040). Respondents describing animal production as their main occupation tended to have greater reliance on chicken sales for their income. Consideration is given to estimating the offtake from the flock and the financial contribution to the household.     

Newcastle disease virus strain I2--a prospective thermostable vaccine for use in developing countries.

Forty-five avirulent Australian strains of Newcastle disease virus had been examined for antigenicity in chickens and 18 of these were tested for thermostability. Strain I2, chosen for a combination of antigenicity and thermostability, was artificially selected for enhanced thermostability. Master seed material was then prepared in minimal disease eggs, and vaccine by a further two passages in conventional eggs. Strain I2 virus at seed and vaccine level induced adequate levels of antibody in chickens vaccinated by eye drop and usually in their contacts. The serological response to oral vaccination was less certain. Antibody titres indicative of substantial protection against virulent challenge were maintained in a simulated village flock for 38 weeks by vaccination of the foundation flock on two occasions, with subsequent vaccination confined to clutches of chicks as they were produced. Strain I2 virus survived for at least 12 weeks when stored at 22 degrees C in 1% gelatin. Strain I2 is suitable for local production of thermostable vaccine in regional laboratories in developing countries.     

Survivability and causes of loss of broody-hen chicks on smallholder households in Bangladesh

We determined the flock sizes and rates of loss caused by different factors in broody-hen chicks (BHC) up to 60 days of age on 600 randomly selected smallholdings in Bangladesh. The smallholders were beneficiaries of a village poultry production chain called ‘Smallholder Livestock Development Project-2’ (SLDP-2) which was undertaken with the financial assistance of the Danish International Development Agency (DANIDA). For estimating survival time of BHC, we observed chicks in 80 smallholdings. SLDP-2 aims at ameliorating poverty among women by poultry rearing at village level; in total, 104,000 key rearers, constituting 96% of all of the beneficiaries of the SLDP-2 area, were enrolled in 26 upazilas (a lower administrative unit of Bangladesh). A key rearer is a smallholder who rears at least five ‘Sonali’ (RIR × Fayoumi) and some indigenous (desi) chickens in a semi-scavenging system. Sonali chickens are supplied from the development project, and have higher egg production while the broodiness of the desi hens is exploited to get chicks hatched for future stocks; thus, the chicks hatched and reared to 60 days old at key rearers’ households are called BHC. In this study 32% of the smallholders had BHC each month. At the beginning of a month, the median number of chicks in a flock was 8, and the mean survival time was 50.5 days. Incidence rates of loss of BHC from disease, predation, selling and slaughtering were 0.102, 0.086, 0.009 and 0.002 per chick-month at risk, respectively. The major predators were crows, mongooses and eagles with incidence rates of loss being 0.018, 0.016 and 0.010 per chick-month at risk, respectively. Colibacillosis (both single and mixed infections) contributed to the death of 21% of dead BHC collected; Newcastle disease and salmonellosis contributed to the next highest (14 and 12%) proportional mortalities.     

Experimental trials with a thermostable Newcastle disease virus (strain I2) in commercial and village chickens in Tanzania

Antibody responses in indigenous village and commercial chickens vaccinated with 12 thermostable Newcastle disease (ND) vaccine and protection levels against challenge with a virulent field isolate were determined. The antibody response of village chickens vaccinated by eye drop revealed that 30, 60 and 90 days after primary vaccination, the mean log2 HI titres were 6.1, 5.4 and 3.6, respectively, whereas for commercial chickens, the antibody response after 14, 30 and 90 days were 8.2, 5.1 and 4.2, respectively. Village chickens vaccinated orally via drinking water had mean log2 HI titres of 3.4 after 30 days. After booster vaccination, the mean HI titre was 5.4 and 3.3 after 30 and 60 days post-secondary vaccination (i.e. 60 and 90 days after primary vaccination). Antibody response of mean log2 HI titres of 2.6 was recorded 30 days after primary vaccination orally through food; 30 and 60 days after secondary vaccination (i.e. 60 and 90 days after primary vaccination), mean log2 HI titres were 5.3 and 3.2, respectively. All commercial and village chickens vaccinated by eye drop survived the challenge trial whereas village chickens vaccinated through drinking water and food had protection levels of 80% and 60% 30 days after primary vaccination, respectively. However, 30 days after booster vaccination, the protection level was 100%. At 60 days after secondary vaccination, the protection level dropped again to 80% for chickens vaccinated orally. All control chickens used in the challenge trials developed clinical ND and died 3-5 days after inoculation with the virulent virus. Supported by laboratory findings, I2 strain of NDV seemed to be avirulent, immunogenic and highly protective against virulent isolates of NDV. It may be a suitable vaccine to use in village chickens to vaccinate them against ND in rural areas.     

Postvaccination viremia in breeding flocks of layers and broilers after vaccination against Marek's disease of fowl

The immunity state after vaccination against Marek's disease (MD) was studied in three multiplier flocks of laying fowl (MFL), five multiplier flocks of broiler fowl (MFB), and one commercial layer flock (CLF). The occurrence and average titres of post-vaccination viraemia in the selected sets of chickens from these flocks, examined at the age of three or twenty weeks, were used as the immunity criterion. The development of post-vaccination viraemia, following the administration of the MARVAK vaccine at the doses of 100 and 1000 PFU per bird in the HX-SL and Shaver layer hybrids, was examined under laboratory conditions at the same time. In the group of birds examined in the third week of age and coming from the MFL vaccinated with the recommended MARVAK vaccine (dose (100 PFU per bird), 64.3% of the chicks were viraemic, the average viraemia titre being 12 PFU/10(7) leucocytes. After the administration of a four-fold vaccine dose, 57.1% of the chicks were viraemic, the average titre being 3.2 PFU/10(7) leucocytes. After the administration of a ten-fold dose of MARVAK vaccine, 80% of the chicks were viraemic and the average titre of viraemia was 8 PFU/10(7) leucocytes. In the MFB vaccinated with the recommended dose of the MARVAK vaccine, the percentage of viraemic chickens was 48.3% and the average titre of viraemia was 6.5 PFU/10(7) leucocytes. In the pullets examined at the age of 20 weeks the number of viraemic birds ranged from 20 to 50% and the average viraemia titres were from 3.8 to 13.1 PFU/10(7) leucocytes. In the flock affected by acute MD, no post-vaccination viraemia was found in the clinically diseases pullets. In the chickens of the HX-SL line vaccinated with the recommended MARVAK vaccine dose, viraemia culminated in the third week after vaccination (31.5 PFU/10(7) leucocytes), and after the use of the dose ten times as high as the recommended one the culmination came a week later (47 PFU/10(7) leucocytes). In the Shaver chicks vaccinated with the recommended dose or with the ten-fold dose of the MARVAK vaccine, the post-vaccination viraemia culminated in the fourth week after vaccination (94.9 and 116.8 PFU/10(7) leucocytes). The post-vaccination precipitation antibodies were first detected in the eighth week after vaccination.     

Husbandry and trade of indigenous chickens in Myanmar—Results of a participatory rural appraisal in the Yangon and the Mandalay divisions

There is a variety of professions working with village chickens in developing countries, including farmers, veterinarians and chicken traders. People from all these occupations were involved in a participatory rural appraisal to investigate husbandry practices and trade of village chickens in Myanmar. Data were collected in two climatically different regions of the country, in the Yangon and in the Mandalay divisions. The breeding and training of fighting cocks was practised only in the Mandalay division, with well-trained birds sold for very high prices. Apart from this, chickens were raised in both regions mainly for small disposable income and were generally sold when money was needed, in particular during religious festivals. Chicken traders on bicycles, often called ‘middle men’, usually purchase birds from farmers in about 10 villages per day. Several ‘middle men’ supply birds to wealthier chicken merchants, who sell these birds at larger chicken markets. There is in general limited knowledge among farmers about the prevention of Newcastle disease via vaccination. Commercial indigenous chicken production is practised in Myanmar, but family poultry farming dominates indigenous chicken production in the country.     

Assessing the productivity of indigenous chickens in an extensive management system in southern Nyanza, Kenya

The present study was conducted to assess the performance of indigenous chickens under extensive system in southern Nyanza, Kenya. The study was carried out in two phases in Komolorume and Kawere villages in Rongo and Rachuonyo districts, respectively. The first phase was a cross-sectional study in 81 farms selected by cluster sampling to get the overview of the indigenous chicken production. A four-month prospective longitudinal study in 60 farms randomly selected from the previous 81 farms followed. Mean flock sizes per household were 20 and 18 birds in Komolorume and Kawere, respectively. Overall mean flock size was 19 birds ranging from 1to 64. The mean clutch size, egg weight and hatchability were 12 eggs, 48 g and 81% respectively in Komolorume and 10 eggs, 45 g and 70%, respectively, in Kawere. The chick survival rates to the age of eight weeks were 13% and 10% in Komolorume and Kawere, respectively. Mean live weights for cocks and hens were 2096 g and 1599 g in Komolorume and 2071 g and 1482 g in Kawere, respectively. The mean household cock to hen ratio was 2:5 and 2:4 for Komolorume and Kawere, respectively. The mean chick to grower to adult ratio per household was 8: 6:6 in Komolorume and 8:4:6 in Kawere. Clutch sizes and hatchability rates were significantly higher in Komolorume village (P?<?0.5). The productivity of the indigenous chickens was shown to be low compared to that of the improved chickens in other parts of the world.     

Prevalence and incidence of Newcastle disease and prevalence of Avian Influenza infection of scavenging village chickens in Timor-Lesté

A longitudinal study to monitor prevalence and incidence of antibodies against Newcastle disease (ND) virus and prevalence of antibodies against Avian Influenza (AI) virus in scavenging village chickens was conducted in 20 villages within 4 districts of Timor-Lesté. A total of 3600 blood samples was collected from 1674 individual birds in 300 household chicken flocks during three sampling periods (December 2008-February 2009, March-May 2009, and June-August 2009). The mean interval between household visits was 101.6±1.9 days. None of the birds enrolled in the study was vaccinated against ND or AI. A haemagglutination inhibition (HI) test was used to determine antibody titres against ND virus and a competitive ELISA and HI tests were used to detect antibody against AI virus. The bird-level ND seroprevalence pooled across all samplings (adjusted for clustering by households) was 4.4% (95% CI 3.5-5.2). The bird-level ND seroprevalence in each of the three sampling periods (adjusted for clustering by household) was 3.0% (95% CI 2.0-4.0), 6.6% (95% CI 5.1-8.0) and 3.6 (95% CI 2.5-4.6), respectively. A total of 12.6% individual birds tested ND seropositive at least once over the total study period (95% CI 10.5-14.7). The flock-level ND seroprevalence (at least one bird tested had antibodies against ND virus) pooled across all samplings was 15.9% (95% CI 13.5-18.3). A total of 35.3% flocks had a minimum of one bird being ND seropositive at least once over the study period. The bird-level incidence rate for the period between the first and the second sampling and between the second and the third sampling was 5.6 (95% CI 4.1-7.5) and 0.5 (95% CI 0.5-3.8) per 10,000 bird-years-at-risk, respectively. A total of 1134 serum samples from the last sampling period between June and August 2009 was tested for antibodies against AI virus. Only 4 samples tested Influenza A positive, indicating a bird-level seroprevalence level for Influenza A of 0.4% (CI 0.0-0.7%). These Influenza A positive samples were further tested for HI antibodies against AI virus subtypes of H5N1, H5N3, H7N3 and H9N2, but all tested negative, suggesting that the influenza antibodies in those four birds resulted from exposure to low pathogenic AI viruses of different H subtypes. Our results indicate that village chickens in Timor-Lesté are exposed to ND virus; there was a higher risk of infection during the early months of 2009 than either immediately prior or subsequent to this. No evidence of infection of village chickens with H5, H7 or H9 AI viruses was detected in this study.     

Cecal carriage of Clostridium perfringens in broiler chickens given Mucosal Starter Culture.

Day-of-hatch broiler chicks housed in isolation units were each given, by oral gavage, 0.1 ml of Mucosal Starter Culture (MSC) or saline control. Each of the treated and control chicks was subsequently given a composite culture of three strains of bacitracin-resistant Clostridium perfringens (Cp) previously isolated from chickens with symptoms of necrotic enteritis. Some chicks were maintained on a corn-based diet provided ad libitum. Others were given the feed supplemented with 50% rye (a predisposing factor for necrotic enteritis). At 7, 14, and 21 days after receiving Cp, chicks were euthanatized, and cecal contents were diluted and plated on selective agar containing bacitracin. For chicks on corn feed, Cp numbers were similar in control birds and birds given MSC in three of four trials. In two of the trials that demonstrated no effect of MSC on Cp numbers, enterotoxin presence was determined. The number of birds with detectable Cp enterotoxin in their small intestine and the mean toxin levels were lower in the MSC-treated birds. In a fourth trial with birds on corn-based feed, mean Cp numbers and the number of Cp-positive birds were lower in the MSC-treated birds. For the two trials involving chickens on rye-supplemented feed, Cp numbers and the percentage of Cp-positive birds were significantly reduced in MSC-treated birds compared with control birds. Enterotoxin in birds receiving the 50% rye diet was at low levels or not detected in control and MSC-treated birds. Results suggest that MSC may reduce intestinal proliferation of Cp, a causative agent of necrotic enteritis in poultry and of foodborne disease in humans.     

Detection of avian encephalomyelitis virus

Methods for the detection of two strains of avian encephalomyelitis virus (AEV) in chick embryo brain cell cultures and chickens were compared. It was found that the agar gel precipitin test (AGPT) and the enzyme-linked immunosorbent assay (ELISA) carried out on the serum of inoculated chickens were more sensitive than either the indirect fluorescent antibody test in cell cultures or the detection of clinical signs in chicks. On the basis of results obtained in this experiment the effects were then determined of routes and time of inoculation of chickens on the detection of AEV. It was found that birds infected at two weeks old produced higher antibody titres than one-day-old birds and the AGPT and ELISA detected comparable levels of antibody in them. It was recommended that the tests to detect the presence of AEV as a contaminant of vaccines be replaced by a serological test carried out on chicks inoculated intramuscularly at two weeks old.     

Investigations of the vertical transmission of Erysipelothrix rhusiopathiae in laying hens

Erysipelas was diagnosed in a layer breeder flock in Sweden in 2002. Although vertical transmission of Erysipelothrix rhusiopathiae has not been previously described in chickens, the potential of erysipelas infection to adversely affect hatching eggs was of concern. To clarify the possible impact of erysipelas on hatching eggs and their progeny, an experiment was done using 200 hatching eggs collected from the infected flock. The eggs were incubated for 21 days, and the egg shells, infertile eggs, dead-in-shell embryos, and a sample of day-old hatched chicks and blood samples from 5-day-old chicks were cultured for E. rhusiopathiae. In addition, after 28 days of grow-out, the male chickens were euthanatized and cultured for the bacterium, and the remaining female chickens were placed as a backyard flock and observed over a 4-mo period. Bacteriological test results of the above-mentioned samples were negative for E. rhusiopathiae. Mortality rates were not excessive, and no clinical symptoms of erysipelas were observed during the period of observation. The result of the investigation suggests that in layer breeder chickens, E. rhusiopathiae is not vertically or egg transmitted and that the disease outbreak in the parent stock had no adverse impact on the quality of hatching eggs in terms of increased embryo mortality.