1. The economic effects of increased vitamin E supplementation in 168 commercial broiler flocks incorporating over 3 million birds was assessed using a computerised data retrieval system. 2. Approximately half of the flocks were fed on either a high (163 mg/kg) vitamin E or on a normal (44 mg/kg) vitamin E‐containing diet throughout production. 3. Approximately half of the flocks were the progeny of breeder flocks which had been fed on a high vitamin E‐containing diet throughout production. 4. The improvement in target income in the vitamin E‐supplemented broiler flocks was 8–44% (P < 0.01). 5. The residual improvement in target income in these flocks, after the cost of the additional vitamin E was taken into account, was 2.74% and failed to reach statistical significance. 6. The increased net income was achieved by a significantly improved food conversion ratio and average weight per bird (P < 0.05). 7. There was no overall effect of vitamin E supplementation of broiler breeders on subsequent broiler performance. |