The area requirements for pastures or paddocks associated with a run-in shed will vary depending upon the number of animals housed together; the soil type, fertility, and slope; forage types; and climate.
A general rule is to provide two to three acres per horse for year-round grazing unless the horses are supplementally fed. Provisions for winter hay feeding will be necessary.
Pastures or paddock layout should be planned to accommodate rotation of pastures. Depending upon stocking rate of horses, a pasture rest period can be provided for individual pastures to allow regrowth and recovery from grazing.
Ashley Griffin, University of Kentucky