@article{peebles_burnham_gardner_brake_bruzual_gerard_2001, title={Effects of Incubational Humidity and Hen Age on Embryo Composition in Broiler Hatching Eggs from Young Breeders ,}, volume={80}, ISSN={0032-5791}, url={http://dx.doi.org/10.1093/ps/80.9.1299}, DOI={10.1093/ps/80.9.1299}, abstractNote={There is a paucity of information regarding the influence of incubational humidity on the characteristics of broiler embryos from young hens that often produce chicks of marginal quality. Therefore, the effects of broiler breeder age (26, 28, and 30 wk) in young broiler breeders and incubator humidity (43, 53, and 63% RH) on embryonic growth between 16 and 21 d of incubation, hatching chick weight, and embryo and chick body compositions were evaluated. Hatching broiler chick BW at 21 d was lower for 26-wk-old breeders compared to those at 28 and 30 wk, and the lowest RH decreased relative wet embryo weight. Embryonic growth, on wet and DM bases, was increased in eggs from the youngest hens. Embryo moisture content (EM) was lower at 16, 17, and 19 d of incubation in eggs from breeders at 26 wk when compared to those at 28 wk of age. The effects of RH on embryo crude protein and fat composition were not consistent and varied with breeder age and length of incubation. It was demonstrated that broiler breeder age affects embryogenesis and hatching chick BW. Furthermore, EM was influenced by breeder age, and changes in incubational RH between 43 and 63% affected embryogenesis without having associated effects on EM or consistent effects on embryo crude fat and protein content. Nevertheless, a depression in embryogenesis with a reduction in incubational RH to 43% may accentuate poor posthatch performance of chicks from young breeders.}, number={9}, journal={Poultry Science}, publisher={Elsevier BV}, author={Peebles, E.D. and Burnham, M.R. and Gardner, C.W. and Brake, J. and Bruzual, J.J. and Gerard, P.D.}, year={2001}, month={Sep}, pages={1299–1304} }
 @article{burnham_peebles_gardner_brake_bruzual_gerard_2001, title={Effects of Incubator Humidity and Hen Age on Yolk Composition in Broiler Hatching Eggs from Young Breeders}, volume={80}, ISSN={0032-5791}, url={http://dx.doi.org/10.1093/ps/80.10.1444}, DOI={10.1093/ps/80.10.1444}, abstractNote={The effects of broiler breeder age (26, 28, and 30 wk) and incubator relative humidity (43, 53, and 63% RH) on yolk sac weight and composition in broiler hatching eggs between 16 and 19 d of incubation were evaluated. Percentage yolk sac weight was reduced in eggs from the youngest (26 wk) breeder hens and in eggs incubated at 53% RH. Percentage yolk moisture, in eggs from the youngest hens, was lowest at 16 d and was highest at 19 d, and percentage yolk lipid was highest at 16 and 17 d of incubation in eggs from 30-wk-old hens. Percentage yolk lipid content was higher at 63% RH compared with 53% RH in eggs from 26-wk-old breeders but was lower in eggs incubated at a 43% RH compared with 53 and 63% RH from 30-wk-old breeders. Yolk stearic and arachidonic acid concentrations were higher and myristic acid concentration was lower in eggs from the 26-wk-old hens. Conversely, the highest yolk concentrations of linolenic and palmitoleic acids occurred in eggs from 30- and 28-wk-old breeders, respectively. At 16, 17, 18, and 19 d of incubation, yolk oleic acid concentrations were significantly, but variably, affected by breeder age, whereas linoleic acid concentration was highest in 26-wk-old breeders only at 19 d. Palmitic acid concentration at 17 d was lower in eggs incubated at 53% RH compared with 43 and 63% RH. Rate of yolk uptake from the yolk sac by embryos may be increased by incubating eggs at 53% RH, and the effects of changes in RH between 43 and 63% on yolk lipid content are influenced by breeder age.}, number={10}, journal={Poultry Science}, publisher={Elsevier BV}, author={Burnham, M.R. and Peebles, E.D. and Gardner, C.W. and Brake, J. and Bruzual, J.J. and Gerard, P.D.}, year={2001}, month={Oct}, pages={1444–1450} }
 @article{peebles_gardner_brake_benton_bruzual_gerard_2000, title={Albumen height and yolk and embryo compositions in broiler hatching eggs during incubation}, volume={79}, ISSN={0032-5791}, url={http://dx.doi.org/10.1093/ps/79.10.1373}, DOI={10.1093/ps/79.10.1373}, abstractNote={The relationship of albumen height (AH) to the compositions of yolks and embryos in hatching eggs from a young (30 wk of age) broiler breeder flock was evaluated during incubation. On Day 2 of incubation, egg weight, yolk weight, and yolk moisture, lipid, and fatty acid contents were determined in eggs from broiler breeders previously identified as laying eggs of either low or high AH. In addition, egg weight, wet and dry embryo weight, and embryo moisture and protein contents were determined on Days 10, 12, and 16, and embryo lipid content was determined on Days 12 and 16. Yolk and embryo weights were expressed as percentages of sampled egg weight. Egg, yolk, and wet embryo weights, yolk moisture and lipid contents, and embryo moisture, protein, and lipid contents were not affected by AH; however, yolk myristic acid concentration was higher, and yolk linoleic acid concentration was lower, in low AH eggs on Day 2 of incubation. Furthermore, on Day 16, dry embryo weight was significantly higher in low AH eggs. Young breeder hens laying eggs of different AH may also produce egg yolks with different fatty acid compositions. Differences in yolk fatty acid profiles between AH groups during early incubation may impact subsequent embryo DM weight without associated effects on embryo moisture, protein, or lipid contents.}, number={10}, journal={Poultry Science}, publisher={Elsevier BV}, author={Peebles, E.D. and Gardner, C.W. and Brake, J. and Benton, C.E. and Bruzual, J.J. and Gerard, P.D.}, year={2000}, month={Oct}, pages={1373–1377} }
 @article{bruzual_peak_brake_peebles_2000, title={Effects of relative humidity during the last five days of incubation and brooding temperature on performance of broiler chicks from young broiler breeders}, volume={79}, ISSN={0032-5791}, url={http://dx.doi.org/10.1093/ps/79.10.1385}, DOI={10.1093/ps/79.10.1385}, abstractNote={Broiler hatching eggs were subjected to one RH condition (53% RH) from 0 to 16 d and switched to one of three different RH conditions (43, 53, or 63%) from transfer at 16 d to pull time at 21.67 d of incubation. The broiler breeder ages were 27, 29, and 31 wk for Trial 1, and 26, 28, and 30 wk for Trial 2 in Experiment 1. For both trials, BW at hatch, BW at pull, hatch time, and chick weight loss between hatching and pull were measured. All unhatched eggs were opened and examined macroscopically. Experiment 2 was conducted using the chicks produced in Experiment 1. The chicks were immediately placed after pull and randomly distributed by sex into brooding pens by RH treatment in Trial 1, and by sex, RH, and brooding temperature in Trial 2. Two brooding conditions, warm and cool, were used in Trial 2. Body weight at placement, BW gain to 12 d, feed conversion, and mortality were recorded. There was no effect of RH treatment on fertile hatchability. Body weight at hatch, pull, and placement increased with hen age. Mortality was higher for the late-hatching chicks in the warm brooding conditions in Trials 1 and 2 of Experiment 2, whereas mortality was significantly greater for the early-hatching chicks and those chicks hatched at 43% RH under the cool-brooding temperature conditions. Relative humidity treatment had no effect on chick performance in the presence of warm brooding conditions. Warm brooding conditions improved BW gain to 12 d compared with cold brooding conditions. Overall, optimal chick performance was achieved at 53% RH. Chick quality problems that may be due to high or low RH during incubation can be ameliorated by proper brooding conditions.}, number={10}, journal={Poultry Science}, publisher={Elsevier BV}, author={Bruzual, J.J. and Peak, S.D. and Brake, J. and Peebles, E.D.}, year={2000}, month={Oct}, pages={1385–1391} }