We study groups of autonomous robots engaged in a foraging task as typically found in some ant colonies. The task is to find a prey object and a nest object, establish a path between the two, and transport the prey to the nest. Once a path is established, robots are recruited to the prey, self-assemble into a pulling structure and collectively transport the prey—which is too heavy for a single robot to move it—along the path to the nest. We follow a swarm-intelligence based control approach. All robots have the same controller. They self-organise into teams and sub-teams that accomplish a number of different tasks concurrently. To solve the subtask of exploration and path formation we propose a new approach, that is, chain formation based on cyclic directional patterns (CDP chains). At present, we believe this study to be the most complex example of self-organisation in the robotics field. Experimental results with groups of 2, 4 and 8 physical robots confirm the reliability and robustness of the system.