Agroforestry and, more precisely, the integration of animals into orchards, represent an interesting source of income diversification for fruit growers who are confronted with rising climatic and economic risks. Besides farm resilience and optimisation of land use, this association seems to provide reciprocal benefits for both trees and animals, such as: nutrient cycling, weed management, natural protection and pest control. In particular, poultry and, more specifically, chickens, have caught the attention of numerous fruit growers in search of simple and time-saving agroecological solutions to regulate pests and weeds in their orchards. Yet, whereas traditional silvopastoral systems involving livestock have been extensively studied, the advantages and disadvantages of introducing chickens into orchards have been overlooked.
In this review, we aimed to build a heuristic representation of a chicken-pastured orchard in order to better understand this complex agroecosystem. We also compared the scientific state-of-the-art concerning some characteristics of this system to situations in the field.
We first carried out a synthesis using an initial set of information (scientific articles, grey literature, testimonies, etc.) to build a simple heuristic representation based on compartments in interaction. We then examined the nature of information on interesting interactions by comparing 86 scientific articles to 26 farmers' testimonies.
We show that the scientific and empirical knowledge concerning chicken-pastured orchards is uneven. More precisely, we identified four types of divergence on some characteristics of the information from different sources concerning the system. One general finding is that the absence of consensus about crucial aspects of the complex dynamic of chicken-pastured orchards and a lack of quantification approaches on several interactions are not consistent with farmers' needs. We suggest that including farmers in the scientific process as well as fostering interdisciplinary systemic approaches, notably between agronomy, animal science and ecology, could greatly benefit the study and design of agroecological integrated systems such as chicken-pastured orchards.
To our knowledge, this review is the first one to present a global view of chicken-pastured orchards. The review built around the heuristic model aims at helping scientists identify knowledge gaps and new research questions. In addition, the heuristic model can also be a useful tool for designing and managing innovative systems together with the farmers concerned.