Infertility caused by male management problems is common. Problems may be caused by an inadequate number of healthy males or because males have reduced sperm production resulting from chronic disease, inadequate feed intake, or starvation (harsh feed restriction). However, obese females may be less efficient in transporting sperm to the infundibulum, resulting in reduced fertilization of the ovum as it is released from the ovary. The male must be dominant to the females, or mating will not occur. Commercial turkey hens are inseminated artificially with semen collected from the toms and used the same day. Parthenogenesis is responsible for some infertility in turkeys. There are host sperm glands in the oviduct of females, and live sperm can be retained for 3–4 weeks. Waterfowl have a rudimentary penis, and prolapse of the penis is occasionally reported in drakes. There is no treatment.