It is designed to maximise weight gain by providing ad-lib feeding during the weaning stage and the following months leading to the sale period. The hopper unit (with gates removed) may be placed in the creep area at calving down stage in order to introduce young stock to the appropriate feed ration. This approach will ensure that stock are less dependent on milk at the weaning stage. It is not designed as a shelter – this is the reason for the open-back pen. Our trials and feedback confirm that closed-in units restrict the process as young stock need time to get used to entering the darkened units, and in bad weather they stay inside for the shelter the unit provides. This restricts the ad-lib process and does nothing for weight gain.