The most common louse in sheep is the biting or chewing louse (Bovicola ovis), which are small, pale to red/brown flat insects feeding on skin debris and hair, living within the centimetre of the wool closest to the skin.
Lice do not produce a definite scab lesion and can be found anywhere on the sheep. Heavy infestations are associated with sheep in poor health.
Infested sheep rub and scratch and the fleece appears rough and pulled, with numerous loose strands of wool. Sheep can bite and nibble at the fleece. Lice can be confused with sheep scab. However, unlike scab, sheep with lice are less likely to have a reflex to nibble at affected areas when they are touched in handling.