From the FarmPlate glossary:
Small farms are often also family farms. A small farm is defined by the USDA as a farm with less than $250,000 gross receipts annually, on which day-to-day labor and management is provided by the farmer (or the farm family that owns or leases the land). Small farms typically have fewer animals or less acreage, greater diversity of production and higher-quality products than larger or industrial farms as a natural result of greater attention to the health of both the land and the animals. Many believe that the preservation and growth of small family farms is vital to a sustainable food system because our health, environment and communities are so closely linked to food production.