| Popis: |
THE increasing importance of the commercial production of the small-sized roaster turkey on a year around basis necessitates a continuous supply of hatching eggs. The relatively short reproductive period of the turkey requires the use of several breeding flocks throughout the year to assure a constant supply of eggs. Normally turkeys can be brought into egg production and will lay at an economical rate nearly anytime of the year, except during the summer months. During this season of the year, egg production is generally poor and usually persists for a relatively short period of time. Therefore, many year around growers have difficulty in securing poults during this season of the year. The review of Burger (1949) on the seasonal reproduction of wild birds, such as the starling, indicates that reproduction in seasonably producing wild birds can only occur when a refractory period has been experienced and dissipated. The refractory period … |
