Photoperiod and seasonal influences on the growth of turkey hens

1. The influence of photoperiod and time of year on the growth of hen turkeys was investigated. 2. Photoperiod treatments consisted of computer simulations of day lengths which occur naturally in the spring and autumn of the year. Both photoperiod treatments were given to hens in the autumn and spring. 3. Data were collected for growth evaluations at 2‐ to 4‐week intervals to 16 weeks of age. No significant season × photoperiod interactions occurred. 4. The spring trial resulted in greater body weights and better food conversions (food/gain) than the autumn trial. 5. Simulated autumn daylengths resulted in greater body weights and improved food efficiency at 16 weeks of age compared with simulated spring daylengths. 6. The pattern of growth (period changes) was influenced by season, but not photoperiod. 7. Season and photoperiod both have important and independent influences on the growth of the turkey hen.