79.2.3. If a manure storage works, another works aimed at reducing pollution or a works aimed at reducing the inconvenience caused by the odours from a breeding unit can only be erected by encroaching upon the space that must be left open under separation distance requirements, the erection is allowed notwithstanding the separation distance requirements so long as the works is not erected on the side facing the building used for a purpose other than an agricultural purpose whose siting would entail the greatest restriction on the potential for expanding the agricultural activities of that breeding unit if the separation distance requirements were taken into account.