Participant exit and reentry over short time spans ("churn") in the Supplemental Nutrition Assistance Program (SNAP) is costly to program participants and administrators. In the first empirical attempt to identify causes of churn, we combine California employment and SNAP caseload data to determine whether churn increases with agricultural employment and which characteristics of agricultural employment cause churn. We find (1) that churn rates are higher with more agricultural employment and (2) that variability in employment is a cause of churn; this effect is larger in counties with more agricultural employment. We conclude with relevant policy recommendations.