The Planet Earth Primer offers useful information on zero-grazing. They explain, "zero-grazing means keeping animals in a stall, and bringing fodder to them instead of allowing them to graze outside. It is also sometimes called "cut-and-carry". The description below is about how to keep dairy cattle using zero-grazing. It is an intensive system that produces a lot of milk from a small amount of land."
"Zero-grazing can also be used with goats and sheep. They can be kept in a shed with a slatted wood or bamboo floor raised about 1 m above the ground. The droppings fall through the slats into a pit beneath the shed. They can then be carried away to be used as fertilizer."
The Planet Earth Primers also explains that "zero-grazing is especially useful in areas where land is scarce. It requires a reliable source of food and sufficient labour to cut and carry the feed" and there are a few advantages and disadvantages to using this method.
Source: Planet Earth Primer, "Farm Animal Livestock: Zero-Grazing".