Turkeys currently have the shortest reproductive cycle and produce the fewest eggs of any poultry species. Commercial turkey breeders rely on management procedures to extend turkey hens' egg-laying period and discourage nesting and incubation. The breeders have found it increasingly difficult, however, to identify and manage nesting hens in commercial operations that typically consist of 20,000 to 30,000 hens per flock. Large white turkey hen on a nest of eggs.
Turkeys currently produce the fewest eggs of any poultry species.
The scientists have discovered that elevated circulating concentrations of the hormone prolactin inhibit hens' ovarian function, stimulate nesting behavior, and decrease egg production. With the long-term goal of increasing egg production by controlling amounts of circulating prolactin, the investigators have undertaken additional studies to learn more about the physiological factors regulating prolactin synthesis and release. The scientists have developed sophisticated surgical techniques to collect blood from tiny vessels connecting the hypothalamus and the pituitary gland. Although the neuromechanisms regulating reproductive behavior are not yet clearly understood, VIP is a known physiological stimulator of prolactin secretion in turkeys. Studies have demonstrated, for example, that turkeys displaying nesting behavior have elevated brain levels of the hormone.