A complexity analysis was performed on the behaviour time series of four groups of seven chickens (Gallus gallus domesticus) using the detrended fluctuation analysis (DFA). DFA quantifies the fractal-like correlation properties of behaviour sequences on short time scales (seconds) over active periods of approximately 0.5 h (2050 s). In this study the level of randomization of locomotor and resting sequences was related to the rearing conditions of chickens. The complexity of locomotor sequences decreased with high stress (food limitation). Adding a sand substrate increased the complexity of other activities such as perching, foraging, and resting but reduced the complexity of locomotor behaviour due to the display of sand bath behaviour. In addition, the correspondence between the complexity of behaviour sequences and age was more pronounced under control situations than under stress (food limited). Under stress it appeared that therewas not enough energy to perform complex adult behaviour.