Why do sheep always seem to be chewing?

Nature has given this characteristic to animals such as sheep who, while they are grazing, are watched by carnivores such as wolves and eagles. Only when they are safe in their pens do they actually chew the food they have eaten.
All ruminating animals (sheep, goats and cows, for example) have a different organic structure from other animals. Their stomachs are divided into four compartments, and when the animal grazes, the grass is swallowed almost whole and is deposited in the belly, the first of the stomachs. It undergoes a first digestion there, then it is returned to the mouth where it is chewed, and then it goes to the other three stomachs. It is quite common to find sheep lying on the ground and chewing in this manner, and this is known as ‘chewing the cud’.