@article{siopes_neely_1999, title={Ahemeral lighting of turkey breeder hens. 3. Temporary application and early age at lighting}, volume={78}, ISSN={["0032-5791"]}, DOI={10.1093/ps/78.3.387}, abstractNote={Ahemeral (non-24 h) light-dark cycles are known to increase egg size but when applied continuously have adverse effects on egg production. The purpose of this experiment was to determine whether temporary application of ahemeral light-dark cycles (AH) can overcome the adverse effects of continuous AH and provide improved reproductive performance of turkey hens photostimulated at an early age. Of particular interest was the effect of temporary AH on increasing egg weight at the start of lay because decreased egg weight is a major problem associated with early lighting of turkey hens. The AH treatments started at 26 wk of age and were given for 2 wk, 5 wk, or continuously. Each consisted of 15 h of light per cycle with a cycle length of 28 h duration, that is, 15 h light (L):13 h dark (D). The experiment was started in the winter season and continued for 28 wk. The following variables were measured: BW, feed intake, onset and rate of lay, fertility, hatchability, incidence of floor eggs, egg weight, poult production, and poult weight. It was clear that 5 wk or more of AH followed by standard lighting (15L:9D) increased initial egg weights from those of 26-wk controls and were similar to those of 30-wk controls. This effect was temporary, as it was absent by 8 wk of photostimulation. Also, cumulative eggs per hen to 54 wk of age were increased by 5 wk of AH treatment as compared to those of controls photo-stimulated at 30 wk of age. These eggs had normal fertility, hatchability, and poults per hen in two evaluation periods. A high incidence of AH floor eggs was reduced to that of the controls following a shift to standard light-dark cycles. We concluded that temporary use of AH at the start of photostimulation is better than continuous use of AH throughout lay and resulted in improved reproductive performance of hens photostimulated at an early age.}, number={3}, journal={POULTRY SCIENCE}, author={Siopes, TD and Neely, ER}, year={1999}, month={Mar}, pages={387–391} }
 @article{siopes_neely_1997, title={Ahemeral lighting of turkey breeder hens .1. Cycle length effects on egg production and egg characteristics}, volume={76}, ISSN={["0032-5791"]}, DOI={10.1093/ps/76.5.761}, abstractNote={A study was conducted to determine the effective range of light-dark cycle lengths for reproductive performance in turkey hens. The treatments consisted of seven different light-dark cycle lengths: 21, 23, 24, 26, 27, 28, and 30 h each with a 15-h photophase per cycle. Data were collected for BW, feed intake, livability, onset and rate of egg production, egg weight (EW), shell thickness, and weight of egg components. The results indicate that turkey hens can be induced to lay eggs with light-dark cycle lengths other than 24 h (ahemeral) with practical extremes being about 23 to 28 h. Egg production in the ahemeral treatments never significantly exceeded that occurring in the 24 h group and the percentage of floor eggs increased at cycle lengths greater than 26 h and at 21 h. Cycle lengths of 21 and 30 h provided the most extreme deviations in the quantity and quality of eggs from those obtained on a 24 h cycle length. Shell thickness increased consistently as cycle lengths increased from 23 to 30 h. Egg weight increased in a curvilinear manner as cycle lengths increased or decreased from 24 h. This increase was associated with increases in shell, yolk, and albumen weight; however, the contribution by each was inconsistent, varying by cycle length as well as time on treatment. It may be concluded that an effective practical range of light-dark cycles for turkeys is 23 to 28 h and that 28 h is a reasonable limit to maximize EW and shell thickness while minimizing a reduction in egg production.}, number={5}, journal={POULTRY SCIENCE}, author={Siopes, TD and Neely, ER}, year={1997}, month={May}, pages={761–766} }
 @article{siopes_neely_1997, title={Ahemeral lighting of turkey breeder hens. 2. Early age at lighting and reproductive performance}, volume={76}, ISSN={["0032-5791"]}, DOI={10.1093/ps/76.12.1783}, abstractNote={An experiment was conducted to determine whether ahemeral lighting (AH) could be used to obtain increased egg weight and poult weight and otherwise normal reproductive performance in Large White turkey hens lit as early as 26 wk of age. The experimental design utilized a 2 x 2 factorial arrangement of treatments that evaluated two light cycle lengths (24 h, control and 28 h, ahemeral) at two hen ages (26 and 30 wk). Treatments were continued for 24 wk and the following variables were measured: BW, feed intake, onset and rate of lay, fertility, hatchability, incidence of floor eggs, egg weight, poult production, and poult weight. As compared to the response of hens in the control lighting treatment, ahemeral lighting increased egg weight and poult weight early in the lay period only and resulted in delayed onset of lay (+3.4 d) and depressed egg production (-7 eggs to 54 wk of age). Percentage fertility and hatchability were similar between ahemeral and control treatment groups. However, ahemeral lighting decreased the number of poults per hen when started at 26, but not 30, wk of age. Hens photostimulated early at 26 wk of age were delayed in onset of lay by 5.9 d but produced more eggs per hen to 54 wk of age (95.8) than hens photostimulated at 30 wk (89.7); however, during equivalent lay periods, egg production was similar between the two groups. Early lighting did not have an adverse effect on fertility, hatchability, or poults per hen but egg weight and poult weight were depressed. It was concluded that although ahemeral lighting increased egg weight and poult weight in turkey hens photostimulated early, continuous application of ahemeral lighting throughout the lay period had adverse effects on some components of reproductive performance.}, number={12}, journal={POULTRY SCIENCE}, author={Siopes, TD and Neely, ER}, year={1997}, month={Dec}, pages={1783–1788} }