The invention discloses a coop with adjustable space size. The coop comprises a coop main body, the coop main body is internally provided with a space adjusting assembly, the space adjusting assembly is composed of a baffle plate, a slide block, a connecting rod, a push block, a slide groove, a connecting hole and a connecting pin, the top of the coop main body is provided with a top door assembly, the top door assembly is composed of a rotating shaft, a top door and a handle, side door assemblies are symmetrically arranged on the two side faces of the coop main body, each side door assembly is composed of a rotary shaft, a side door, an inserting hole, a sliding rail, a moving block, a spring, a connecting block, a clamping piece and an operating rod, and an excrement storage assembly is arranged at the bottom of the coop main body and composed of an excrement storage cavity and a cleaning device. The coop has the advantages that the internal space of the coop can be adjusted, the coop can be divided into a plurality of parts to conveniently distinguish whether the chickens are injected with vaccines, the coop door is convenient to open and close, excrement is convenient to export and clean and the like, and the problems that the coop changing process is quite complex, operation such as taking out the chickens for vaccine is inconvenient to distinguish, and the coop is seriously polluted are solved.