Zoning can have a significant impact on farm viability. Zoning ordinances define agricultural uses and determine what kinds of activities are allowed by right or are considered accessory (subordinate to agriculture but related) or ancillary (unrelated). They also determine when uses are conditional and/or require special permitting. Once defined, ordinances usually include performance standards to guide the appearance, intensity, scale, and scope of associated structures. Thus, what communities include in zoning ordinances can make or break a variety of on-farm economic opportunities, depending on local priorities.