Primitive sheep like Bighorns in the West still shed most of their wool every year. ... But for the majority of sheep, there is continual, year-round wool growth.

How do sheep naturally get rid of wool?

Sheep didn't always need to be sheared; people breed sheep to produce excess wool. Wild sheep (and certain types of “hair” breeds like the Katahdin) will naturally shed their coarse winter coats. They do this by scratching their bodies against trees and rubbing away their extra fluff as the weather warms up.

What happens if a sheep's wool is not cut?

If a sheep goes too long without being shorn, a number of problems occur. The excess wool impedes the ability of sheep to regulate their body temperatures. This can cause sheep to become overheated and die. Urine, feces and other materials become trapped in the wool, attracting flies, maggots and other pests.