Don't know why we don't have this yet, but we should have a silkfarmer credo, dependent on lumberjack and farmer. The bonuses could be as follows
1. Dexterity and sewing +10
2. Increased number of leaves harvested from mulberry trees
3. Silk worms can survive missing two meals
4. Chance to get three filaments per cocoon unraveled
5. Small quality bonus to unraveling silk cocoons