I came up with this SOW Tractor after giving some thought to the issue of having sows highly mobile, highly contained and safe healthy and happy.
It also solves a problem I've seen in pasture management. If you'll notice alot of hay farmers get further and further from the feild edge every Cutting to avoid damaging their cutters.
Running a pig tractor around your feild edges and pasture fringes allows you to make use of otherwise fallow ground harvest soft mass, legumes, and grasses improve sow health and cut down on actual feed inputs. This improves efficiency and effectiveness making it more cost effective to keep breeder sows herd and a boar. It also improves the ground was well.