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.     

Productivity of Local Chickens under Village Management Conditions

The productivity of local chickens under village management conditions was studied in six villages situated in three climatic zones within Morogoro District in Tanzania. Two villages were picked in each climatic zone (warm and wet, warm and dry, cool and wet) for the study. The data were obtained by actual measurement, qualitative observations and interview of members of the households directly responsible for the care of chickens. In addition, data sheets were given to selected farmers to record the performance of their chickens. The mean flock size for the three zones was 16.2, with a range of 2 to 58. The overall mean clutch size, egg weight and hatchability were 11.8, 44.1 g and 83.6%, respectively. The overall mean chick survival rate to 10 weeks of age was 59.7%. The mean live weights for cocks and hens were 1948 g and 1348 g, respectively. The mean growth rates to the age of 10 weeks were 4.6 g/day and 5.4 g/day, while those from 10 to 14 weeks of age were 8.4 g/day and 10.2 g/day for female and male birds, respectively. The age at first lay ranged between 6 and 8 months, and the average hen had three laying cycles per year. Most of the chickens were left to scavenge during the day and were provided with simple housing at night (95.2% of the owners). Only small amounts of supplementary feeds were occasionally given and minimal health care was provided. It was concluded that the low productivity of chickens was partly due to the prevailing poor management practices, in particular the lack of proper health care, poor nutrition and housing.     

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.     

Effect of two different commercially available white light LED fixtures on broiler hatchability and chick quality

1. The objective of this study was to evaluate the effect of two different spectra of white light on hatchability and chick quality of broiler chickens.

2. A total of 8424 Ross 708 broiler eggs were divided over three light exposure treatments during incubation: No light (DARK), a light emitting diode (LED) light with high levels of blue light (BLUE), or a LED light with high levels of red light (RED). Hatchability, embryo mortality and chick quality were assessed at hatch.

3. DARK had a higher percentage of chicks with unhealed navels (21.1 ± 1.3%) and fewer overall chicks with no defects (77.0 ± 1.2%) compared to both the BLUE (9.9 ± 0.9% and 88.4 ± 1.1%) and RED treatments (7.7 ± 0.8% and 90.2 ± 1.0%).

4. Both the BLUE (80.9 ± 1.0%) and RED treatments (82.9 ± 1.4%) had higher hatchability of fertile eggs than the DARK treatment (76.0 ± 2.2%).

5. These results indicate that either of these LED fixtures could be used to improve hatchability and chick quality in broiler chickens. Utilising these types of lightings in commercial hatcheries will improve the efficiency via increased hatchability and quality of the chicks hatched.     

Guinea fowl (<Emphasis Type="Italic">Numidia meleagris</Emphasis>) production by small-holder farmers in Zimbabwe

Guinea fowls are a source of high-value meat and eggs, and the birds are more disease resistant than other types of birds. A survey was conducted in ward 23, Chipinge district, Zimbabwe, to characterise guinea fowl management practices and to identify constraints and potential opportunities for increased guinea fowl productivity. Purposive sampling was used to select 84 out of possible 252 guinea fowl owners. Data were collected by direct observation on guinea fowl varieties, feeding strategies and housing facilities. A semi-structured questionnaire was used to collect data on farmer experiences, perceptions and common challenges encountered. A chi-squared test was conducted using the IBM SPSS Statistical Package for Social Sciences (SPSS) version 21. The study revealed that famers keep guinea fowls under free-range management. The average production indices were flock size 18 ± 12, egg production 89 ± 50, hatchability 63.8% and keet survival rate of 75%. Approximately 42.9% of the farmers provide supplementary feed albeit not systematically. There was a significant association between provision of supplementary feed and keet survival rate (χ ² = 21.600, df = 2, P < 0.016) as well as provision of housing and flock size (χ ² = 38.508, df = 3, P < 0.018). The housing provided was substandard. Major challenges faced by farmers were predation, low hatchability and lack of access to profitable markets. The provision of supplements and better housing for birds could improve guinea fowl productivity.     

Footpad dermatitis in broiler chickens in Japan

The prevalence of footpad dermatitis (FPD) in broiler chickens in Japan was investigated. In the first examination at slaughterhouses, lesions were commonly observed on the footpads of a total of 8,985 broiler chickens from 45 flocks on 36 farms. In 3 flocks, all the birds examined had lesions. In the other 42 flocks, the incidence of FPD ranged from 31.9% (81/254) to 99.5% (1/222). The footpad lesions were classified into 4 categories according to the severity of dermatitis as follows; score 0, 1,181 birds (13.1%); score 1, 2,992 birds (33.3%); score 2, 3,000 birds (33.4%); and score 3, 1,812 birds (20.2%). The mean scores of the flocks varied widely from 0.31 to 2.69. Males had higher mean scores than females. No significant differences were found between the mean scores of birds reared in windowless houses and those in open-sided houses. On 4 farms, the investigation was carried out in different seasons, and 3 of them showed higher mean scores in winter than in summer. Next, observation of 2,255 birds from 15 flocks on 5 farms during a 4-week rearing period revealed that FPD was already produced at 7 days of age and worsened with age.     

Dynamic Modelling of a Traditional African Chicken Production System

A dynamic stochastic model, SimFlock, was developed with the purpose of simulating the dynamics of a traditional African chicken flock at smallholder level. The model simulates outputs, e.g. total number of chickens produced, egg production and net return after entering flock, or area-specific biological parameters. Biological parameters include hatchability, egg production, growth and survival of various age groups, full-grown weights as well as some decision parameters like farmers' need for meat consumption, and slaughtering and selling age of chickens. A simulation job is defined by 'states of nature' (biological parameters specified directly or drawn at random from the hyperparameters), number of replications and number of days to be simulated. Three simulation jobs were selected to demonstrate the use of the model: one with the default settings; one with collection of eggs for 20 days; and one in which growth rate was increased to double. After simulation, the results of each job were compared in relation to total number and weight of chickens produced, egg production and net return. SimFlock could be used as a management or extension tool to identify the biological parameters of major influence on production. Improvement of these parameters will have the largest impact on output.     

Sero-prevalence of avian influenza among broiler-breeder flocks in Jordan

Thirty blood samples were collected randomly from each of the 38 breeder-broiler farms in Jordan. Serum samples were examined using indirect ELISA for specific antibodies to avian influenza virus. The overall true flock-level sero-prevalence of avian influenza was 71% (95% CI: 55,83). Positive flocks had 2-30 sero-positive chickens and half of flocks had >20 sero-positive birds. The number of sero-positive flocks varied in the studied localities with more sero-positives in farms located within the migratory route of migratory wild fowl. The examined broiler-breeder flocks had no clinical signs, or noticeable decrease in egg production; mortalities were within the normal range (0.1-1%). The number of positive sera/flock correlated with flock size. There were a no significant (Pearsons r=0.21, p=0.21) correlation between positive flocks and age. A non-pathogenic AI virus infects broiler-breeder farms in Jordan. Wild local and migrating birds might promote the further spread of this virus in Jordan and other countries.     

Egg production,fertility, hatchability and immune responses of some chicken strains under high ambient temperatures

This experiment was designed to investigate and compare the egg production, fertility, hatchability and immune responses of some local developed Egyptian chicken strains under high ambient temperatures. A total of 108 (26 weeks old) laying hens of Matrouh, Silver Montazah, Mandarah and Inshas (9 hens × 3 replicates × 4 strains) were used to evaluate the impact of thermal stress (24-34ºC) during summer season (June, July and August) on egg production, fertility, hatchability and immune responses. The obtained results revealed that final body weight (FBW/g) and body weight change (BWC/g) among different chicken strains were not affected. The daily feed consumption (FC/g) and feed conversion ratio (FCR) for Silver Montazah and Inshas strains were significantly (p ≤ .05) higher than those of Matrouh and Mandarah strains. The mean egg production (EP/%) and egg mass (EM) for Silver Montazah and Inshas strains were significantly (p ≤ .05) higher than those of Matrouh and Mandarah strains. The highest percentages of hatchability of total eggs (HTE) and fertile eggs (HFE) were recorded in Inshas chickens, while the lowest value was recorded in Mandarah chickens. Also, the highest embryonic mortalities (p ≤ .05) and lowest chick weight at hatch (CWH/g) were recorded in Mandarah chickens compared with the other strains. The highest values for antibody titres against phytohemagglutinin-P (PHA-P) were recorded in Mandarah chickens, while the least values were recorded in Inshas chickens.     

Effect of hydrogen peroxide disinfection during incubation of chicken eggs on microbial levels and productivity.

Hatchery sanitation has a significant impact on chick quality. The proper use of disinfectants is essential. Aerosol bacterial counts, egg moisture loss, hatchability, chick quality, and broiler productivity were measured in eggs exposed to hydrogen peroxide fogging and compared with eggs not exposed to disinfectant during the incubation period. Hydrogen peroxide was also evaluated in the presence of a severe challenge with Staphylococcus aureus-contaminated eggs. A significant reduction was found in aerosol bacterial counts within the hatcher when incubators were fogged with 3% hydrogen peroxide when compared with water-fogged machines even in the face of high bacterial challenge. Eggs exposed to hydrogen peroxide lost a significantly greater amount of moisture during incubation, but hatchability was not affected. The use of hydrogen peroxide as a hatchery sanitizer did not affect broiler livability, body weight, or feed conversion but did reduce the incidence of retained yolk sacs in 42-day-old chickens.     

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.     

Prevalence and factors associated with it,of birds dead on arrival at the slaughterhouse and other rejection conditions in broiler chickens

1. Standardised data on husbandry were recorded for a flock of birds in one house on each of 150 broiler farms in the UK during the 4 d prior to slaughter.

2. For each flock, the incidence of birds found dead on arrival (DoAs) and the Meat Hygiene Service carcase rejection records were recorded at the slaughterhouse.

3. The mean percentage of birds in each flock found DoA was 0·12% (range 0–0·64%) and the mean percentage of Total Carcase Rejects (TCRs) for each flock was 1·23% (range 0·07–5·51%).

4. A general linear model was developed to examine factors associated with flock percentage DoAs. Assuming a linear relationship, all other factors remaining the same, a one percentage point (PP) increase in small/emaciated birds will result in a 0·155 PP increase in DoAs and a 1 PP increase in wheat in diet 4 will result in a 0·003 PP decrease. An increase by one in the total number of vaccines administered will cause a 0·029 PP decrease in DoAs, a 1 g increase in live weight at slaughter will be associated with a 0·000043 PP increase and a 1 PP increase in mortality on farm would be associated with a 0·000044 PP increase. A 1 PP increase in Ross birds decreases DoAs by 0·0004 PPS: there is also a seasonal effect.

5. The model developed for flock percentage TCRs found that a 1 PP increase in wheat in diet 3 will result in a 0·052 PP decrease in TCRs and a 1 PP increase in Ross birds will cause a 0·009 PP decrease. A 1 PP increase in birds culled on farm will be associated with a 0·03 PP increase in TCRs and the diagnosis of disease during the flock cycle increases TCRs by 0·397 PPs. A one day increase in age at slaughter will result in a 0·046 PP increase in TCRs.     

Diseases of indigenous chickens in Bokaa village, Kgatleng district, Botswana

This study examined flock size and management, level of internal and external parasite burden and seroprevalence of antibodies to poultry pathogens in indigenous chickens in Bokaa village, Kgatleng district, Botswana. The mean flock size was 22.6 +/- 6.85 with a range of 11-34. The mean body weights of cocks and hens were 2.28 +/- 0.56 kg and 1.70 +/- 0.38 kg, respectively. Housing and commercial poultry feed were not provided. Ascaridia galli, Heterakis gallinarum and Syngamus trachea were found in some birds. Although the chickens were not vaccinated against any poultry diseases, serum antibodies to Newcastle disease, infectious bursal disease and infectious bronchitis were detected.     

Comparative study of the effects of organic selenium on hen performance and productivity of broiler breeders

1. A 10-week experiment was conducted with Ross 308 broiler breeder chickens in cages to evaluate the influence of organic and inorganic sources of selenium (Se) supplementation. A total of 600 birds at 29 weeks of age were divided at random into 4 groups and fed on a maize–soya basal diet supplemented with different forms of Se.

2. The first (control) group was given the basal diet without Se supplementation, whereas the second, third and fourth groups were given, respectively, the basal diet with 0.3 mg/kg of inorganic Se in the form of sodium selenite or 0.3 and 0.5 mg/kg of organic Se in the form of Se enriched yeast (Se-yeast).

3. The experiment was carried out for 10 weeks to compare and evaluate the influence of Se supplementation on breeder performance, egg production, hatchability and the quality of eggs. Samples were collected for analysis at weeks 0, 5 and 10 of the experimental period.

4. At the end of the experiment (39 weeks), there was a reduction in mortality in breeders given diets supplemented with 0.5 mg/kg of Se-yeast. Supplementation of feed with 0.5 mg/kg organic Se increased egg production, percentage of settable eggs and hatchability.

5. Selenium supplementation increased egg weight and specific gravity compared to the control diet. However, no significant variation was found in albumen or yolk protein content at the end of week 10.

6. Selenium accumulation and glutathione peroxidase (GSHPx) activity were lower in the egg albumen and yolk of control compared with Se-supplemented treatments. Se accumulation and GSHPx activity were higher in the group given 0.3 mg/kg organic compared to 0.3 mg/kg of inorganic Se.

7. The results favour the use of Se-yeast at the dose of 0.5 mg/kg in broiler breeder diets for better productivity of eggs, settable eggs, hatchability and higher Se accumulation and antioxidant status in eggs.     

Mortality rates adjusted for unobserved deaths and associations with Newcastle disease virus serology among unvaccinated village chickens in Myanmar

Village chickens are an important livestock for many rural families in Myanmar and other developing countries. Village chickens are kept under free-ranging conditions, with confinement only at night. Therefore, it is likely that some deaths are not observed by farmers. We conducted a longitudinal study from November 2003 until May 2004 to describe temporal patterns of mortality of village chickens in 10 villages in Myanmar. Field veterinarians first identified the numbers of birds in all chicken-owning households in each village. We then selected 307 households randomly with stratification by flock size. Each study household was then visited once monthly at which time questionnaires were completed recording current flock structure and numbers of hatchings, mortalities, sales and birds consumed since the previous visit. In addition, sera were collected from a sample of adult birds and growers. Depending on month and age group of chicken, from 71 to 231 (out of 290-307) households had discrepancies in the counts of birds. For chicks, at least one-quarter of the households had unobserved losses of at least 5 chicks per household (maximum 66 chicks); unobserved losses were less for growers and adult chickens. The median month-specific, village-specific mortality rates per 1000 bird-days at risk (counting missing birds as deaths) ranged from 0.8 to 1.7 for adults, from 0.4 to 4.7 for growers and from 8.0 to 16.5 for chicks. Across all birds, the prevalence of protective titres against Newcastle disease virus was 79% (95% confidence interval 74, 84); higher prevalences of protective titres were associated with reduced mortality rates in the following months.     

Production objectives and trait preferences of village poultry producers of Ethiopia: implications for designing breeding schemes utilizing indigenous chicken genetic resources

To generate information essential for the implementation of breeding schemes suitable for village poultry producers in Ethiopia, a survey was conducted aimed at defining the socioeconomic characteristics of the production environments in different geographic regions, understanding the important functions of chickens, identifying farmers’ choice of chicken breeds and the underlying factors that determine the choice of genetic stock used. The survey included both questionnaire survey and a participatory group discussion. A total of 225 households (45 households from each of five Woredas) were interviewed. The questionnaire was designed to collect data covering general information on village poultry production such as socio-management characteristics, production objectives, population structure, breed choice and trait preferences, market preferences of specific traits, and farmers’ selection practices. The participatory farmers’ discussions were designed to involve stakeholders in defining the breeding objective “traits” and deriving their relative importance in the production environment based on the different functions of chickens and “traits” identified in the interviews. The results showed that production of eggs for consumption is the principal function of chickens in most regions followed by the use as source of income and meat for home consumption. The production system in all geographic regions studied revealed similar features generally characterized by extensive scavenging management, absence of immunization programs, increased risk of exposure of birds to disease and predators, and reproduction entirely based on uncontrolled natural mating and hatching of eggs using broody hens. Farmers’ ratings of indigenous chickens with respect to modern breeds showed the highest significance of the adaptive traits in general, and the superior merits of indigenous chickens to high yielding exotic breeds in particular. Adaptation to the production environment was the most important attribute of chickens in all the study areas. The high significance attributed to reproduction traits indicates the need for maintaining broody behavior and high level of hatchability while breeding for improved productivity of indigenous chickens for village conditions. The market price of chickens is primarily dictated by weight, but farmers rated growth (males) and number of eggs followed by growth (females) as the production traits they would like the most to be improved. Therefore, the ultimate breeding goal should be to develop a dual-purpose breed based on indigenous chicken genetic resources with any of the comb types other than single for all the regions studied having the most preferred white body plumage for farmers in the Amhara region and red body plumage for those in Oromia, Benshangul-Gumuz, and Southern regions.     

Livestock production in central Mali: Reproduction,growth and mortality of domestic fowl under traditional management

In an 18-month study the domestic fowl in 42 households in three traditional management systems were recorded to determine reproduction, growth and mortality parameters. There were significant differences for all systems combined in the number of clutches started per month with the lowest number being laid in the cool dry season of January and February. Mean number of eggs per clutch was 8.8; the number of eggs increased significantly throughout the career of the hen but there were no significant systems differences. Egg weight was 34.4g there being no significant differences due to age of hen or system. Intervals between clutches were 92 days, annual egg output was 35 per hen (assuming that birds were present in the flock for a year) equivalent to about 118% of mean adult hen body weight: hens actually in the flocks during the study had produced 2.1 clutches on average. Hatchability of eggs was 69.1% there being significant seasonal and systems differences in this parameter, lowest hatchability being in the hot dry season (March to June) and in the rainfed millet system. Mortality rates to eight weeks were 56% of chicks hatched. Growth to 10 weeks averaged 4g/d. Mature cocks weighted 1.60 kg and mature hens 1.02 kg: hen weights were significantly affected by reproductive state, laying hens being heavier than both incubating hens and those rearing chicks, while those rearing chicks were heavier than those incubating. Suggestions for improving productivity are made.     

A study of the epidemiology of infectious bursal disease in poultry in Queensland, 1976–1979

The epidemiology of infectious bursal disease (IBD) was studied by serology and sometimes by visual examination of the bursa of Fabricius in poultry flocks in Queensland during 1976–1979.
Ten flocks, each of approximately 30,000 meat breeding chickens, were surveyed. All chickens had maternally-derived antibody against IBD virus (IBDV) at hatching and active antibody was not detected while the chickens were brooded on rearing farms. When distributed to breeding farms, 7 of the flocks developed antibody when 11 to 25 weeks of age. The remaining 3 flocks were vaccinated by infection of 10% of the birds and within 4 weeks more than 80% of the chickens had developed precipitating antibody to IBDV.
Blood samples of 20 to 30 broiler chickens were collected at slaughter (7 to 9 weeks of age) from each of 312 broiler flocks raised on 37 contract farms. While the samples from 21 flocks were without detectable antibody to IBDV, all serum samples for 263 flocks contained antibody. The ratio of bursal weight to bodyweight was significantly lower in birds from 144 flocks having antibody to IBDV than in birds from 10 flocks that were without detectable antibody. In sequential studies, IBDV antibody became demonstrable in 27 of 30 flocks when the chickens were one to 6 weeks of age and was accompanied by bursal atrophy.
Serological investigation of 4 flocks of layer breeding chickens on a multi-age farm at approximately monthly intervals resulted in antibody to IBDV being detected at every examination.
Serological tests and bursal examinations were carried out weekly in 2 flocks each of 4000 layer chickens between one and 20 weeks of age. Serum antibody developed in one flock at 4 weeks of age and in the other at 17 weeks of age. In both flocks, bursal atrophy occurred concurrently with the development of antibody.     

Antimicrobial resistance in fecal Escherichia coli isolated from growing chickens on commercial broiler farms

To investigate the effects of rearing practices of commercial broiler chickens on the incidence of antimicrobial resistance in commensal Escherichia coli isolates, fecal E. coli isolates obtained in 4 farms were screened for anitimicrobial resistance. Ten E. coli isolates were recovered from each of the fecal samples collected from 10 birds in the farms at the ages of 2 days, 14-17 days, and 47-50 days. In 2 out of the 4 farms, no antimicrobials were used during the rearing period. In the other two farms, following collection of the fecal samples at 14 and 15 days of age, oxytetracycline (OTC), sulfadimethoxine (SDMX), and tylosin were given to birds on one farm and SDMX was used in the other. Isolates resistant to ampicillin and OTC that were obtained from an untreated flock at different sampling times were closely related to each other by pulsed-field gel electrophoresis patterns (PFGE) of XbaI-digested chromosomal DNA. PFGE analysis together with in vitro conjugation experiments suggested that diversity of resistance phenotypes within a clone may be resulted from the acquisition and loss of R-plasmids in an untreated and a treated flock. The numbers of resistance phenotypes observed among fecal isolates increased during the growth of the chickens in all the farms. The results in the present study suggest that persistence of commensal E. coli strains resistant to antimicrobials even in the absence of antimicrobial administration. It is also hypothesized that horizontal transmission of resistance determinants resulted in the emergence of different resistance phenotypes in those farms.     

Production of quail-chick chimaeras by blastoderm cell transfer

1. Quail-chick chimaeras were produced by injecting dissociated quail blastoderm cells into chick embryos. 2. Quail blastoderms were removed from the yolk and the cells were dispersed by trypsin treatment or pipetting. The cell suspension (1 to 5 microliters) was injected into the subgerminal cavity of unincubated chick embryos. The chick embryos were then cultured in recipient eggshells. 3. Quail blastoderm cells injected into the chick embryos adhered to the chick embryonic cells. The rates of hatching were 8.6% (38 chicks from 441 eggs) and 40.3% (48 chicks from 119 eggs) when the volumes of the cell suspension injected were 3 to 5 microliters and 1 microliter, respectively. 4. Seven out of 86 hatched birds were clearly identified as being chimaeric because part of the feather colouring was of quail specificity. In addition to these chimaeric birds, there were 8 chimaeric embryos which died before hatching. The distribution patterns of the quail feathers were varied among the chimaeric birds and embryos. 5. This technique provides a basis for the investigation of chick embryo cryopreservation, genetic transformation and analysis of cell lineage of chickens.