The objective of the present study was to ascertain the effect of in ovo feeding of vitamin E (VE) on the incubation results, quality, and oxidative

Hatchery efficiency is based on hatchability and the number of salable chicks. The hatchery sector has been seeking new alternatives to optimize production rates, including the use of different systems (multistage [MS] or single-stage [SS] machines) to improve incubation conditions. The present study aimed to compare results for hatchability, chick quality, and broiler performance of chicks from 2 incubator systems—MS and SS. The experimental design for hatchability, hatch window, egg weight loss, and chick performance variables was completely randomized with 2 treatments (MS and SS). Performance variables were analyzed as a 2 x 2 factorial arrangement (incubator type x chick sex). Egg weight loss between incubation and transfer was higher for eggs incubated in MS (P < 0.05). Hatchability was higher for eggs incubated in SS (P < 0.05), and chicks in SS had a longer hatch window (P < 0.05). Embryo diagnosis revealed higher final mortality for embryos incubated in MS (P < 0.05), as well as higher percentages of alive and dead pipped and cracked eggs (P < 0.05). Physical quality was better for chicks from SS (P < 0.05). There was no interaction between the studied factors for performance results (P > 0.05). Incubator type did not affect broiler performance for any of the studied ages (P > 0.05), whereas male broilers had better performance than females (P < 0.05). The SS incubation system proved better than the MS system at meeting embryo requirements during embryo development, with better hatching rates and chick quality, although performance variables were not influenced by incubation type.

The present study aimed to ascertain the effects of slow-growing breeder age on embryo development, incubation results, and chick quality and of the interaction between breeder age and hatching time on initial performance. A total of 630 hatching eggs obtained from a commercial flock of slow-growing broiler breeders (Isa Label Naked Neck) were evaluated in 2 experiments. The first experiment evaluated embryo development and hatching results for broiler breeder age treatments of 38 and 51 wk, whereas the second experiment evaluated broiler chick performance. For the second experiment, chicks were distributed in a 2 x 2 factorial randomized block (sex) experimental design consisting of 2 breeder ages (31 or 58 wk) and 2 hatching times (479-485 and 491-497 h). At 18 d of embryonic development, embryos of 51-wk-old breeders were larger than those of 38-wk-old breeders (P < 0.05), whereas yolk-free chick weight was similar (P > 0.05). Embryo organ weight was similar for the 2 breeder ages (P > 0.05); however, there was greater development of intestinal villi for embryos of the 51-wk-old breeders. There were no differences between breeder ages in hatchability and chick quality score (P > 0.05). Yolk-free chick weight at pulling was greater (P < 0.05) for chicks from 51-wk-old breeders. Hatching time did not affect performance from 1 to 7 d (P > 0.05); however, chicks hatching at 491-497 h had better performance from 1 to 28 d than did chicks hatching at 479-485 h (P < 0.05). In conclusion, the age of slow-growing breeders affects embryo villi development and chick weight but does not improve incubation results or chick quality. Chicks hatching later (491-497 h) had better performance results than chicks hatching earlier (479-485 h).

The objective of this study was to evaluate a technique for quantifying eggshell conductance using shell fragments from hatched eggs. Additional objectives were to calculate the correlation between eggshell conductance, porosity, and thickness and correlate these parameters with incubation data. The study design was fully randomized in a 3 × 3 factorial scheme (three egg regions - large end, equator, and narrow end - and three ages of broiler breeders – 29, 35, and 59 weeks). A total of 216 eggs were used, with 24 repetitions for each treatment. Neither conductance nor shell thickness showed any interaction with egg region. Breeder age influenced eggshell conductance, such that it was greatest in eggshells from 59-week breeders (0.323 mg day⁻¹ torr⁻¹), while for 29-week and 35-week breeders, the conductance values found were 0.285 and 0.270 mg day⁻¹ torr⁻¹, respectively. The eggshell thickness was similar in eggs from 29 and 35-week breeders and these were greater than the thickness of eggshells from 59-week breeders. Correlations between mean eggshell conductance and chick body weight and yolk free chick body weight were found significant. There were no correlations between mean eggshell thickness and any of the data evaluated. There were positive correlations between mean eggshell porosity and egg weight loss up to the time of transfer, chick weight, and yolk free body weight. The technique of using eggshell fragments can be used for measuring eggshell conductance. Eggshell porosity is the characteristic that best correlates with incubation parameters.

SUMMARY Broilers are subject to adverse environmental conditions, especially temperature, which decreases performance and increases disease vulnerability. Understanding how the mechanisms involved in thermoregulation of the embryo function is essential for improving production. Studies have shown that thermal manipulation should occur late during embryonic development (14^th to 18^th day of incubation) and factors, such as hormones, neurotransmitters and cytokines, are involved in programming the thermoregulatory system. Several methodologies have been applied in experimental situations regarding the frequency, intensity and duration of thermal stimuli during the embryonic period. Hatching yield can be improved, despite different handling strategies, however, there are still divergent results regarding the ability of birds to adapt to thermal stimuli. Thermal management can alter vascular development and hormone levels in embryos. In contrast to high-temperature thermal manipulation, using lower incubation temperatures can positively influence the quality of newly hatched chicks. In general, positive results were observed for thermal manipulation by cold or heat when embryos were stressed for 2 to 6 h/d. Higher hatchability and performance under normal conditions was observed in experiments using temperatures from 36.4 to 36.7°C. Better performance was seen under heat stress conditions in the final phase (21–35 days) when using temperatures from 39.2 to 39.5°C. Thermal manipulation modulates the expression of heat shock proteins (HSP), which vary with stimulus type (heat/cold), breed, tissue and bird age. Finally, thermal manipulation can be effective in helping birds adapt to the breeding environment; however, it is necessary to refine certain points. The present review found that thermal manipulation during embryo development was effective at increasing hatchability and performance of broilers.

SUMMARY Guinea fowls are an alternative source of high-quality meat and eggs. Several studies have been developed on guinea fowl reproduction, nutrition, management, meat and egg quality, including genetic improvement. However, due to the breeding system used in this species, advances in these areas have been delayed. Guinea fowls have their particular morphological and productive aspects. For example, they have seasonal reproductive characteristics, with an egg production that ranges, depending on the type of system, from 20 eggs in the extensive system to 50–200 in the intensive system. Females are heavier than males, especially when sexual maturity begins. Another characteristic is the presence of a brown-coloured cephalic protuberance in both sexes and its widely varied plumage. Other factors such as fertility and hatchability have yet to be fully elucidated. The storage of guinea fowl hatching eggs also deserves more attention. As in the case of broilers, a longer storage time can negatively affect hatchability and chick quality, emphasising that eggs from young breeders are more resistant to a higher storage time. In the nutrition field, research has focussed on determining nutrient requirements. However, standardised diets and correct nutritional requirements for better performance are still scarce. Lack of knowledge about proper nutrition along with poor genetic selection results in slow growth of the guinea hen. Despite the challenges, guinea fowl meat is one of the alternatives to chicken meat, in terms of access to a source of quality protein and financial profitability in certain markets. Guinea fowl eggs present characteristics of a nutritional supplement to a much greater degree in terms of quantitative and qualitative than other alternative bird species. This review aims to assess several aspects related to guinea fowl production as an alternative species in the poultry industry and its global panorama.