Maine law has since changed, but at one time we had to have run in
shelters for our livestock 12 months out of the year. So back then I thought about building "pods" for sheep, They would be steel and wood structures about as long and wide as big metal dumpsters...I mean the BIG ones. On top would be a roof. The biggest part of the design would be the metal frame and "hook" so that a tri-axle truck could hook onto one of these sheep "pods" and haul it from pasture to pasture. It could only hold 30 sheep or so, but adding multiple "pods" would allow the flock to have the housing required.
As I said, Maine law changed, so this is not required on my farm any longer, but the idea is still sound for others. Lets say they wanted livestock, but did not plan to live forever at their current place, they literally could hire a truck to hook and move the "pod" to their new location. Or they had fields that were 10 miles down the road. To go to pasture, they could haul the pod to the rental field in the summer, then back in the winter.