@article{pyrzak_siopes_1989, title={CHARACTERISTICS OF OVIPOSITION PATTERNS OF TURKEY HENS AND THE INFLUENCE OF DIFFERENT WAVELENGTHS OF LIGHT}, volume={30}, ISSN={["0007-1668"]}, DOI={10.1080/00071668908417133}, abstractNote={1. Characteristics of individual oviposition patterns of turkey breeder hens were determined for 160 d of photostimulation with fluorescent blue, green or red light and with incandescent light. 2. In all treatments most eggs were laid during the afternoon and evening. The maximum frequency occurred at 14.00 to 15.00 h (8 to 9 h after light onset); about 15% of all eggs were laid in the dark period. 3. The hourly oviposition distribution remained unchanged and was specific to individual hens throughout the study period. However, it was highly variable between hens, ranging from highly dispersed to tightly clustered. 4. The total number of clutches per hen did not differ between treatments and eggs were laid in relatively short clutches; 65% were of two eggs or fewer, 30% of three to 5 eggs and only 5% of 6 eggs or more. 5. The oviposition time of the first egg in a clutch was very variable; however, oviposition time became more clustered and uniform as the position of the egg in a clutch increased. 6. Mean time of lay, mean interval between eggs and total lag time were not influenced by light treatment. Mean interval was about 27 h for all eggs and was not influenced by clutch size. 7. Light quality at the intensity used in this study did not appear to play an important role in oviposition patterns of turkey hens.}, number={1}, journal={BRITISH POULTRY SCIENCE}, author={PYRZAK, R and SIOPES, TD}, year={1989}, month={Mar}, pages={151–160} }
 @article{pyrzak_siopes_1986, title={EFFECT OF LIGHT QUALITY ON ERRATIC EGG-LAYING OF CAGED TURKEY HENS}, volume={65}, ISSN={["0032-5791"]}, DOI={10.3382/ps.0650795}, abstractNote={The effect of light quality on erratic oviposition (two eggs laid during a 24-hr-period) and the shell quality of erratically laid eggs of turkey hens in cages during 20 weeks of production were examined. Hens were exposed to one of the following sources of light: blue, green, red, or incandescant for 16 hr of light per day (16L:8D). The intensity of light was equalized among treatments on the basis of equal number of photons (3.0 × 1014/cm2 /sec). The frequency of erratic oviposition was similar for all light treatments, ranging between 13.4 to 15.3% of total eggs laid, and most occurred in two-egg clutches. With erratic ovipositions, the first egg was laid during the daily dark period, whereas the second egg was laid in the daily light period, 11.6 to 13.0 hr later. Oviposition time and shell quality were significantly influenced by light treatment. As wavelength increased, shell weight of the erratically laid eggs decreased. Thus, shell quality and the timing of oviposition of erratically laid eggs may be influenced by light color.}, number={4}, journal={POULTRY SCIENCE}, author={PYRZAK, R and SIOPES, TD}, year={1986}, month={Apr}, pages={795–800} }