A flexible bulk container comprising a top wall, a bottom wall, and at least one sidewall defining an internal space. There is an access portion associated with the top wall for accessing the internal space through an open end of the access portion, and a position marker located at a predetermined position on the access portion for detection by a detector of a robotic system. A stack of flexible bulk containers is also provided. An insert for use with a flexible bulk container is also provided. The insert comprises: a head portion and a tail portion extending therefrom, the head portion having an insert upper edge and the tail portion being sized and shaped for engagement with an open end of a filling spout, and lateral spacer portions extending from the head portion, one on either side of the tail portion.