Economic impact of chicken diseases and other causes of morbidity or mortality in backyard farms in low-income and middle-income countries: a systematic review and meta-analysis.

BACKGROUND

Backyard chicken farming is usually subsistence and predominates in low-income countries and, to a lesser extent, in middle-income countries. Chicken flocks are generally raised by households in a low-input, low-output system in contact with other flocks, livestock, and wildlife. This low biosecurity setting predisposes chickens to diseases and injuries. A systematic review was conducted to assess the impact of diseases and other causes of mortality in backyard chickens from low income and middle-income countries.

RESULTS

The systematic literature review was conducted following the PRISMA guidelines. Databases consulted included: PubMed, Medline in OVID, Scopus, Web of Knowledge, CAB direct, AGRIS, AgEconSearch, Agricola, Google Scholar, CyberLeninka, CNKI, LILACS, TCI, SID and Civilica. Of the 40,121 studies identified, 78 studies were selected. Only a limited number of studies (n = 7) assessed the impact on productivity (weight and egg production losses). Results from the meta-analyses showed that the three main causes of mortality in a production cycle are viral diseases (24.5%, 12.4-42.7), the mix of bacterial and viral diseases (24.2%, 6.2-58.2) and bacterial diseases (11.2%, 4.6-25.0). These three causes of mortality also account for the highest proportion of economic losses for infectious diseases. In the case of non-infectious causes, predation and cachexia are responsible for the highest economic losses in backyard chickens.

CONCLUSIONS

Infectious diseases account for the highest economic and mortality losses examined in the selected studies. However, losses due to other causes, such as predation, should not be overlooked. These results could be used to support animal health policy in informing resource allocation to preventive measures to improve food security.