12.—(1) Where concrete slatted floors are used for pigs kept in groups, the maximum width of the openings must be—
(a)11 mm for piglets;
(b)14 mm for weaners;
(c)18 mm for rearing pigs; and
(d)20 mm for gilts after service and sows.
(2) The minimum slat width must be—
(a)50 mm for piglets and weaners; and
(b)80 mm for rearing pigs, gilts after service and sows.