Possible Clues:

• They sound as if the trees are in the flock
• Pasture mothers
• Certain black sheep
• Maa and company, in "Babe"
• Reportedly exploit wool producers
• They may be in woolly coats or cotes
• Fleecy flock
• Yeanling producers
• She-grazers
• Their milk is used to make Roquefort