Objective: To analyze the task of chicken sales in a popular market poultry shop from the systemic perspective of ergonomics in order to provide solutions that optimize well-being and performance. Methods: The sample consisted of 8 poultry workers from a popular market in Lima. A semi-structured interview, systemic ergonomics approach, and Hierarchical Task Analysis were employed. Physical and mental workload were evaluated. Additionally, anthropometric adjustment was assessed, and the Nordic Questionnaire was used to describe musculoskeletal discomfort in the workers. Results: Awkward postures were observed during customer payment due to the depth of the module and the location of the cash register beyond functional reach. In cutting and bagging tasks, risk from repetitive movements was identified, primarily due to the high pace of attention and time pressure. Forced wrist postures were observed when using the knife, along with different cutting techniques among poultry workers. Not only was physical workload identified, but also moderate mental workload. Incompatibility was observed with the depth of the service module, the height of the cutting table, and the height of the shelves. Musculoskeletal discomfort was reported in the wrists (88%), shoulders (88%), and neck (63%). Conclusions: The work system lacks interaction with poultry workers regarding furniture design, tools, organization, and environment; this may explain the biomechanical physical workload, mental workload, and perception of musculoskeletal discomfort. Redesigning the work system, including modifications to the service module, cutting table, and manual tools, is suggested to optimize well-being and performance.