The Cattle-shelters at Tan-y-Graig each have 10, three-centered, stone-arched openings and are both shown on the first-edition 25? map surveyed by 1886. They each have 9 sawn softwood collar-trusses with bolted lap-joints.
The northern range opens onto a yard and has had almost all its western openings blocked with alternate doorways and window openings. These alterations are in stone with engineering brick to opening surrounds. There are internal brick walls dividing it into four units with internal doorways between them. These were probably loose-boxes for cattle. A central unit has an unusual raised area used by the college to milk sheep in the mid-late C20th, while one original arched opening, to the north, has been retained, possibly as a feed store.
The southern range formerly had a similar arched openings with an open yard, which was enclosed when the covered-yard ranges were built. At this time, the usage was changed, timber partitions were inserted to provide 4 units and a railway made to deliver feed into these new intensive fattening units. The timber partitions also continue over the ceiling of the railway to prevent drafts entering the fattening units. Doorways were also made in the east wall for loading into carts against the present lower level road.
Source: Geoff Ward, 2008 (site visited by Geoff Ward and John Wiles, 11/12/2006).