Two sets of one day old, white leghorn (Victoria Strain) chickens were each orally exposed to 1.0 mg lead nitrate daily for 7 days and subsequently infected with 15 and 30 A. galli eggs. These experimental chickens exposed to lead harboured significantly greater worm burden when compared to unexposed controls leading strong support to the view that lead exposure significantly suppressed their immune response to A. galli infection. It also indicated that exposure of lead prior to infection greatly impaired weakened the immune capability of such chickens.