As others have mentioned, keeping “a” sheep is unkind to the sheep. They need companionship.
The second issue is the backyard. To me, a backyard is asphalt, concrete, brick, flagstones, something like that. Not a field or lawn:
This would be like keeping a sheep in a shed all the time. That means carrying fodder and water to the sheep, and shovelling its manure away – probably through the house. This is acceptable in particularly bad winters for lowland, warm-climate sheep, but many breeds are perfectly adapted to outdoor living all year round. Keeping them “indoors” is cruel.
The type of field a sheep lives in is important. They are not naturally grass-eaters. They prefer ‘forbs’, that is flowering plants – what would be considered weeds in grassland. They’re very useful for clearing grass of forbs, and will only eat grass when the forbs are gone. Smart farmers round my way put sheep in their meadows in the spring to eat the forbs, moving them on before the grass comes in for silage- and hay-making. If your backyard is a grass lawn, consider seeding it with clover and other meadow weeds before investing in sheep.
Contrary to popular opinion, sheep are lively and curious creatures. They enjoy exploring their environment, and can be quite athletic. This means they should have a varied environment in which to live: objects to climb and jump on or off, baskets of hay suspended from trees, scratching posts, hidey-holes, etc. They should also have access to free running water, and a shed: not necessarily anything too elaborate, just somewhere they can retreat to in the heat of the day, or heavy rain or snow. It doesn’t even need to have four walls or a shuttable door, as their combined body heat should keep them adequately warm.
They also require a degree of veterinary care. Worming, drenches, hoof inspection, etc. This may mean you need a ‘crush’, a narrow passage that the sheep cannot turn round in, where treatments and inspections can be conducted. Some farmers build their own semi-permanent structures, some hire them.
Home-made crush, using gates.
And unless you take on a primitive breed, you’ll need to shear them! Many government agricultural departments offer shearing courses for those interested – and courses in animal care generally, which are well worth looking into. Alternatively, you can contact a local sheep farmer who may be prepared to shear your sheep with their own for a fee, or they could put you in touch with a shearer.
Originally appeared on Quora.