In non-cage systems for housing laying hens, perches are an important feature of the environment. However, there is evidence of risks to hens’ welfare from collisions as they move between perches. In this experiment studies were conducted to determine the space required by laying hens to move between obstructed perches. Eighty Lohmann Brown layer hens were reared in floor pens fitted with perches from 1 day of age. After the peak of lay (25 weeks of age), their ability to jump to and from perches obstructed either by inanimate objects or by live hens was assessed in four experiments. The results of this study indicated that, while laying hens are often able to jump from or into a 15 cm space between obstructions, this requires changes in take-off and landing behaviour which incur costs in terms of energy expenditure and the risk of collision.