Pharmacological disruption of broodiness in White Rock domestic fowls.

The administration of bromocriptine (CB154) to broody hens (Gallus domesticus) impaired resumption of lay. Resumption of lay was stimulated in broody birds treated with clomiphene citrate (an anti-oestrogen) alone or following CB154 administration. The increased oviposition rate following a single intramuscular injection (21 mg) of clomiphene was long lasting, persisting for at least 16 weeks after treatment. Treatment of broody hens with clomiphene consistently improved (by 4%) the hatchability of the fertile eggs subsequently laid.