How sheepfolds work
Most of the 3500 sheepfolds in north Wales have just one or two cells and were built as shelters for the sheep, or as somewhere to put injured animals. There is more detail on these and other structures here. However, the larger sheepfolds serve a different purpose. Sheepfolds with 4 or more cells are called multicellular and they represent about 3.5% of the total number (around 100).
Multicellular folds are a way for farmers to reclaim their own sheep when flocks from different farms have been mixing on common grazing ground.
This picture is of a a large sheepfold on Y Gyrn. The local name is Buarthau'r Gyrn. Sheep from the various farms are gathered off the mountains on specific days of the year - such as at shearing time (July) - and the whole flock (which may be well over 1000 sheep), is sent into the gathering pen and from there into the dividing pen in the middle. Each farm which uses the sheepfold has its own cell. The larger the farm flock, the larger its cell. Once a farm has reclaimed its own sheep and put them in their cell, they can be dealt with on the spot or taken down to the farm for further work. The picture shows the names of the farms in the area that used the sheepfold in the 1970s. The section for 'Defaid Diarth' is where stray sheep from neighbouring areas are put, before being reclaimed by their owners.
This picture is taken from a September gathering of the sheep. Farmers all co-operate in the gatherings, which usually take place three times a year, in July, for shearing, September when the lambs are separated from the ewes and sent to market, and October when the sheep are all taken down from the mountain to be sent to winter grazing grounds and to prepare for lambing. Sheep are returned to the mountains for grazing in late Spring.
The sheep are moved from the central dividing pen by means of holes in the walls known as creeps. Wooden or metal gates can be open or shut to move the sheep into different parts of the sheepfold. The sheep are identified by the farmers by their earmarks, know as 'nodau clust' in welsh. Each farm has its own recognisable marking pattern, which is cut into the ear of the lamb when it is born.
This picture shows another sheepfold, with sheep being moved from the gathering pens on the right, through a narrow channel called a race into the three farm cells that surround the race. Sheep not wanted for this particular gathering are let out back into the fields via the small cell on the left of the sheepfold.
A short video of the sorting can be found here.