An experiment with a factorial arrangement of three levels of fennel extract (FE) (0, 50, and 100 mg/kg of diet) and three levels of Vitamin D3 (0, 3500 and 4200 IU/kg of diet) was carried out with 360 Ross 308 broiler breeders after moulting (76 weeks). All diets were isocaloric and isonitrogenous. Breeders were weighed 12 weeks after molting (64 weeks) then randomly distributed into 36 pens such that each pen had a similar body weight (BW) distribution. Each pen consisted of 10 hens and 1 rooster. At 76 weeks of age, the birds received experimental diets for 10 weeks. Egg production (EP), egg weight (EW), egg mass (EM), settable eggs, feed conversion ratio (FCR), body weight gain (BWG), cracked, deformed, double yolk (DY) and peewee eggs were recorded daily and presented biweekly. Entire egg production, egg weight, settable eggs (SE), deformed and cracked eggs were not affected by dietary treatments during the experimental period. However, a numerical trend on settable eggs was observed when diets were supplemented with vitamin D3 (P= 0.06). There was a significant interaction between FE and Vitamin D3 on EM and FCR. FE supplementation to breeder diets significantly decreased double yolk and peewee eggs (P < 0.001). BWG significantly increased with dietary supplementation of FE. The results of the present study suggest that supplementation of 50 mg/kg FE to the corn soybean meal based diets affect EM, FCR, double yolk, peewee eggs and BWG with no adverse effects on EP, EW, settable egg, deformed and cracked eggs.

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