Specialized Sebaceous Glands - Did you know sheep have specialized sebaceous glands, thought to be marking glands?
Sheep have many cutaneous pouches that are lined with sebaceous glands - exocrine glands - which produce lanolin. There are three places where the pouches are located. The infra-orbital pouches are found near the sheep's eyes, the interdigital pouches are just above the sheep's hooves, and the inguinal pouches are near the udder or scrotum.
A. Infra-orbital pouches, two on the face, one in the front of each eye and is larger in the ram than in the ewe.
Sheep use their infra-orbital glands to establish social rank. For example, when competition arises between two grazing sheep, they have been observed to nuzzle each other's preorbital glands. By sending and receiving olfactory cues, this behavior appears to be a means of establishing dominance and of avoiding a fight, which would otherwise involve potentially injurious butting or clashing with the forehead.
four on their feet, on the midline above the hoofs on all four feet.
A thick, oily, translucent secretion is stored in this pouch and is discharged to the skin surface through a duct. This viscid fluid lubricates the tendons of the feet and may let the sheep know where they've previously grazed, a sort of territory marker.
If you notice your sheep limping, check to see if one of the openings has gotten clogged. If so, it usually just requires a gentle squeeze which will express the impaction. If necessary, the glands can be treated with local or systemic antibiotics. My sheep have never required antibiotic treatment.
Inguinal pouches, two
their abdomen near the udder or scrotum.
I couldn't find any reference to the specific use of these, but I wonder if perhaps one of the uses is for the lambs to know the sheep is their mom by the scent secreted from them?