Cummings School’s Marieke Rosenbaum,V14, MG14, or VG14,explains how to prevent exposureTest the soil on your property for lead in all areas the chickens can access, including their coop and any places they may range free. UMass Amherst provides soil tests for a fee (find more information at umass.edu/soiltest).
If you find lead, and restrict birds’ access to secure areas or bring in at least two feet of current clean soil to cover areas where lead was detected. Retest the soil annually,because rainfall and other factors can cause soil shifting and mixing.
Source: tufts.edu