When feeding pregnant sows, optimal body condition at birth is sought to avoid the effects of a deviant nutritional condition on health and performance. Various feeding concepts exist but mainly have a restriction in quantity and renunciation of farm-grown forage in common. An ad libitum liquid feeding system based on farm-grown forage in combination with a sow sorting gate (according to body weight—using mechanical scales) was realized on a commercial swine farm. The sorting gate coordinated access to two feeding areas with rations based on whole plant wheat-silage (WPWS) differing in energy content. In this study with a total of 183 pregnant sows, effects of restrictive dry feeding (System I) were compared with ad libitum liquid feeding based on farm-grown forage (System II). Sows were monitored regarding body condition development during pregnancy by measuring body condition score (BCS), body weight (BW), and back fat thickness (BFT) on different time points. Sow and piglet health (vaginal injuries of sows, rectal temperature during the peripartal period, vitality of newborn piglets) and performance data regarding litter characteristics were also recorded. Body condition development of the sows was absolutely comparable. Performance indicators and the course of birth were also similar but with significantly higher scores for piglet vitality in System II (p < 0.05). The tested concept offers opportunities for more animal welfare and sustainability but remains to be further investigated regarding the repertoire of possibly applied farm-grown forage and the effects of the concept in the transit phase of sows.