Reference metadata describe statistical concepts and methodologies used for the collection and generation of data. They provide information on data quality and, since they are strongly content-oriented, assist users in interpreting the data. Reference metadata, unlike structural metadata, can be decoupled from the data.
The survey of poultry in Bulgaria was introduced in 2004 and covers the following species: chickens, turkeys, ducks, geese, quail, ostrich and guinea fowl. The intention of the study is to provide information of the number, the species and categories of the poultry on December 31, the production of eggs for human consumation, eggs for hatching and poultry for slaughtering in the observed calendar year. The activity of hatcheries is also observed. The study is based on a representative sample of poultry farms, which grow one or more species of poultry.
3.1.1. The main data source of the information
Eggs producers
3.2. Classification system
NUTS classification, Combined Nomenclature
3.3. Coverage - sector
NACE Rev.2 - 01.47 Raising of poultry
3.4. Statistical concepts and definitions
The definition applied to data collection is in line with the EU methodology for statistics on eggs for human consumption.
3.4.1. Definition of eggs for consumption under EU methodology
Yes
3.4.2. If not, specify the definition used.
not applicable
3.4.3. Definition of egg producer under EU methodology
Yes
3.4.4. If not, specify the definition used
not applicable
3.4.5. Definition of laying hens under EU methodology
Yes
3.4.6. If not, please describe the differences
not applicable
3.4.7. Definition of ungraded eggs under EU methodology
Not relevant
3.4.8. If not, specify the definition used
not applicable
3.4.9. Ungraded Eggs provided separately
Not relevant
3.4.10. Additional comments on statistical concepts and definitions
not applicable
3.5. Statistical unit
Agricultural holdings with laying hens
3.6. Statistical population
Statistical survey covers units defined as farms under the Law on Agricultural Census in Bulgaria in 2020 growing one or more types of poultry. New farms established after 2020 are added each year. The new farms are found in different administrative sources such as the Register of agricultural holdings under Ordinance 3/1999 and others.
3.6.1. Physical, economical or other threshold(s) applied to the data collection
The legal threshold for a poultry farm is 50 laying hens. However, due to the existence of other threshold criteria (land management, breeding of other animal species, etc.) during the census of agricultural holdings in 2010 we found many farms producing fewer layig hens. In the farm survey list for annual statistics (on the number of eggs produced and the number of laying hens), holdings growing up to 100 laying hens are included in the sample in several strata, depending on the number of hens raised and whether they breed laying hens only or also other species of birds. The holdings with 100 or more laying hens are surveyed exhaustively.
3.6.1.1. COVERAGE
In 2020, the sample includes 1788 farms with laying hens, accounting for 95% of all laying hens.
3.7. Reference area
The data is representative on NUTS 2 level - 6 statistical regions.
3.8. Coverage - Time
Data on eggs for consumption are available from 2004 to 2018
3.8.1. The first survey/data collection
2004
3.9. Base period
2018
3.10. Other comments
No comment.
4.1. Unit of measure in million
Yes
4.2. Other unit of measures used
not applicable
5.1. Reference period in calendar year based
Yes
5.2. Reference date for number of laying hens
Yes
5.3. Additional comments on the reference period/date used
not applicable
6.1. Institutional Mandate - legal acts and other agreements
An agreement between NSI and MAF. The survey on poultry is included in the National Statistical Program in the Agrostatistics Department plan as a body of statistics in the field of agriculture.
6.2. Institutional Mandate - data sharing
Annual, accordimg to the Natotional Statistical Programme
7.1. Confidentiality - policy
The national confidentiality rules are defined in the Statistics Act. According to Art. 25 individual statistical data as well as statistical information that summarizes data for less than three statistical units or for an aggregate in which the relative share of the value of a studied parameter of one unit is over 85 percent of the total value of this parameter for all units of the population cannot be disclosed or provide.
7.2. Confidentiality - data treatment
The national confidentiality rules are defined in the Statistics Act. According to Art. 25 individual statistical data as well as statistical information that summarizes data for less than three statistical units or for an aggregate in which the relative share of the value of a studied parameter of one unit is over 85 percent of the total value of this parameter for all units of the population cannot be disclosed or provide.
The data are disseminated through a specialized publication on the website of the Ministry of Agriculture and food.
10.3. Dissemination format - online database
Under construction.
10.4. Dissemination format - microdata access
Not applicable.
10.5. Dissemination format - other
National Statistical Yearbook, Agricultural Report of MAF, Agrostatistic Reference Book.
10.6. Documentation on methodology
Metadata are published on the website of the Ministry of Agriculture and Food; Instruction for conducting the statistical survey.
10.7. Quality management - documentation
Guidelines for conducting the survey.
11.1. Quality assurance
By validation rules developed in the Information system for agrostatistics (ISAS) for data control and data entry.
11.2. Quality management - assessment
A comparative analysis of the data with previous years, with other statistical surveys and with administrative data is made.
12.1. Relevance - User Needs
Not applicable.
12.1.1. Data collected for national purposes
The data is used by experts at the Ministry of Agriculture and Food - Livestock Directorate, Analysis and Strategic Planning Directorate, and other directorates, the Union of Poultry Farmers in Bulgaria, the Union of Agricultural Producers and other branch organizations, research institutes and universities.
12.2. Relevance - User Satisfaction
The survey about user satisfaction is not appplicable for this data.
12.3. Completeness
Together with information on laying hens and eggs for consumption, information is also available on other species and categories of poultry, such as hens, broilers, turkeys, ducks, geese, quails, ostrich and guinea fowl, and for the production of eggs by other poultry species; the number of poultry fattened and slaughtered during the reference year.
13.1. Accuracy - overall
The achieved accuracy for laying hens after the survey was cv = 0.39 and for the total poultry number cv = 0.11. Only 6 holdings did not deliver information (1 refusals and 5 holding was not found for an interview) or 0.3% of all respondents. Due to a lack of administrative information, data was not imputed.
13.2. Sampling error
The sampling error is 0.4% for poultry in total and 0.13% for the laying hens.
13.3. Non-sampling error
Not applicable.
14.1. Timeliness
The data are available 105 days after the referent day.
14.2. Punctuality
Using the low threshold for exhaustive survey of poultry allows high accuracy of the obtained results.
15.1. Comparability - geographical
The data is collected in the same way throughout the country.
15.2. Comparability - over time
The problem of the comparability of data by regions (NUTS2) is the difference in the scope of their territory until 2007 and thereafter, resulting from the implementation of Regulation (EC) No 176/2008.
15.3. Coherence - cross domain
For the period 2004 - 2023 there is no interruption in the data series. As a source for comparing the number of breeding birds in the annual statistics, incl.utility laying hens we use the results of the structure surveys - census (2010 and 2020) and the sample structure surveys.
15.4. Coherence - internal
The data are harmonized by coherence between individual groups and categories.
The costs (budget) for the survey are part of the national budget of the Ministry of Agriculture and Food. The information is collected by filling online electronic questionnaire by the respondents or by interview face to face.
17.1. Data revision - policy
Not applicable for the survey.
17.2. Data revision - practice
Not applicable.
18.1. Source data
The data on the number of laying hens and eggs for consumption results from an annual sample survey.
18.1.1. Description of data collection process
The sample of farms with poultry is stratified and provides the necessary coverage in the studied species. The sample was compiled from a list of poultry farms surveyed during the agricultural census in 2020. Farms were divided into six groups according to specialization (type of poultry):
Specialized farms with laying hens;
Specialized farms with chickens for meat (broilers);
Specialized farms with other poultry;
No specialized farms (growing more than one kind of poultry);
Small poultry farms, growing to 10 birds;
Large holdings surveyed exhaustively
New farm (created after 2020).
Each group was divided into subgroups - 14 subgroups (strata) based on the number of poultry in them x 28 districts (NUTS3) = 392 strata total. In a survey in 2023, the sample includes 1788 farms with poultry, of which 1003 with/raising utility laying hens. The sample covers 9.4% of all farms with poultry and 91% of all birds, inc. 95% of laying hens. The data are representative on the level 6 statistical regions (NUTS2). Farms growing 100 or more laying hens (128 holdings) are surveyed exhaustively. The survey is implemented locally by experts on agricultural statistics in the Regional Directorate "Agriculture" - by e-mail or conducting interview with farmers and completing a statistical questionnaire.
18.1.2. Model used as a breakdown based on individual information
Not relevant
18.1.3. Method used for the model
Not applicable.
18.2. Frequency of data collection
Annual.
18.3. Data collection
The information is collected by filling online electronic questionnaire by the respondents or by interview face to face.
18.4. Data validation
Validaton rules are used before and on time in data entry in the information systm (ISAS). Cross-check with other administrative sources.
18.5. Data compilation
18.5.1. Data compilation process - data weighting
The number of laying hens is reported as of 31 December.
18.5.2. Data compilation process
Not relevant
18.6. Adjustment
Not applicable.
The survey is carried out on-the-spot in the holdings by experts on agricultural statistics in the MAF regional offices by e-mail or by interview.
The survey of poultry in Bulgaria was introduced in 2004 and covers the following species: chickens, turkeys, ducks, geese, quail, ostrich and guinea fowl. The intention of the study is to provide information of the number, the species and categories of the poultry on December 31, the production of eggs for human consumation, eggs for hatching and poultry for slaughtering in the observed calendar year. The activity of hatcheries is also observed. The study is based on a representative sample of poultry farms, which grow one or more species of poultry.
15 April 2024
The definition applied to data collection is in line with the EU methodology for statistics on eggs for human consumption.
Agricultural holdings with laying hens
Statistical survey covers units defined as farms under the Law on Agricultural Census in Bulgaria in 2020 growing one or more types of poultry. New farms established after 2020 are added each year. The new farms are found in different administrative sources such as the Register of agricultural holdings under Ordinance 3/1999 and others.
The data is representative on NUTS 2 level - 6 statistical regions.
The achieved accuracy for laying hens after the survey was cv = 0.39 and for the total poultry number cv = 0.11. Only 6 holdings did not deliver information (1 refusals and 5 holding was not found for an interview) or 0.3% of all respondents. Due to a lack of administrative information, data was not imputed.
The data on the number of laying hens and eggs for consumption results from an annual sample survey.
Annual
The data are available 105 days after the referent day.
The data is collected in the same way throughout the country.
The problem of the comparability of data by regions (NUTS2) is the difference in the scope of their territory until 2007 and thereafter, resulting from the implementation of Regulation (EC) No 176/2008.
