Medroxyprogesterone acetate (MPA, Depo-Provera) is a progestin (a form of progesterone), used in the prevention and treatment of several reproductive disorders in female poultry. According to one study, hens given MPA had an average of a 24% decline in egg production when receiving injections. MPA is given to female poultry to prevent ovulation, so birds will stop laying eggs. It has also been shown to decrease ovarian cancer prevalence in domestic hens.
Caution: There are many serious side effects associated with this drug. Poultry with suspected liver disease or suffer from reproductive cancer should not be given MPA. Those that receive long-term treatment are more at risk of developing osteoporosis, resulting from loss of bone mineral density.
MPA can be administered in birds in several different forms--orally via tablets, intramuscular injection (IM) into the muscle, or as an implant just beneath the surface of the skin. In order to be effective, birds need to receive multiple ongoing injections, anywhere from 4 to 12 weeks apart. The length of time between injections varies from bird to bird.