Chlordane (0.1 ppm), DDT (0.1 ppm), lindane (0.1 ppm), ethion (0.5 ppm), atrazine (0.5 ppm), and linuron (0.5 ppm) were added to the ration of laying hens. Only DDT and derivatives were detected in egg yolk prior to feeding the hens on the supplemented ration. Chlordane, DDT, and lindane were detected in egg yolk, and the amounts had increased to a maximum after being fed for 6 weeks. Three weeks after resuming normal feeding, residues were not detectable, or in the case of DDT, had decreased to the control level. No residues of atrazine, linuron, or ethion were observed in eggs, abdominal fat, or minced tissues. Prior to feeding the supplemented ration, only DDT and its metabolite DDE were detected in abdominal fat. After feeding the pesticides for 6 weeks, lindane and chlordane were detectable, and DDT and DDE increased 3- and 2- fold, respectively. Three weeks after normal feeding was resumed, lindane and chlordane residues were not measurable, DDT had significantly decreased, and DDE had increased 2-fold. Seven weeks after normal feeding was resumed, DDT had decreased to the control 1eve1, and DDE was approaching control level. Addition of 1% activated charcoal to the ration did not affect significantly the uptake of, or hasten the elimination of the low levels of pesticides fed in the diet. Neither charcoal nor pesticides affected significantly mortality, body weight changes, feed consumption, egg production, egg weight, or eggshell quality.