Unlike other animals, most sheep are unable to shed. The excess wool impedes the ability of sheep to regulate their body temperatures. As long as there are sheep, shearing must be practiced for the health and hygiene of each individual animal.

If a sheep goes too long without being shorn, a number of problems occur. Because shearing too late would mean a loss of wool, most sheep are sheared while it is still too cold. PETA Asia Senior Vice President Jason Baker said: "After exposing cruelty within the English wool industry, we've found the same horrifying abuse of sheep at farms in Scotland. Some sheep went limp during shearing.
However, PETA and its affiliates have continued to expose the same cruelty to sheep in shearing sheds around the world since the RWS was created, and RWS documents were found displayed on a wall in one of the sheds visited in the latest exposé. Despite learning from PETA that wool-industry workers hit frightened lambs and sheep in the face with metal clippers, stomp on them, smash their heads Despite learning from PETA that wool-industry workers hit frightened lambs and sheep in the face with metal clippers, stomp on them, smash their heads into the floor, and abuse them in other ways, Forever 21 still won't switch to wool-free knits. Australia's peak shearing body says animal cruelty cases heard in western Victoria this week have forever changed the industry. A shearer dangled a dying sheep off a shearing platform and propped her against a railing, where she convulsed and died shortly afterward. On one farm, a farmer dragged a sheep, who appeared to be dying, by the leg, allowing her head to bounce along the hard rocky soil for several yards. Sheep farmers have been at pains to point out that undercover footage, which appeared to show shearing contractors abusing sheep, was not representative of the industry.

This can cause sheep to become overheated and die. An estimated one million sheep die every year of exposure after premature shearing.
Scottish sheep farmers slam animal rights group for branding wool 'cruel' SCOTTISH sheep farmers have hit out at an animal rights group which claims wearing wool is “cruel”. Shearing Sheep are sheared in the spring, just before they would naturally shed their winter coats.