Broiler chicks from one incubator hatch within long periods of time, which leads to dehydration and reduction in yolk sac reserves of those chicks that have hatched earlier and potentially impairs early performance. The present research investigated the hatching distribution at intervals of incubation using eggs of different weights within one breeder age or eggs from widely different breeder ages. Eggs from breeders at 27 and 59 weeks of age (54 and 69 g) and from breeders at 40 weeks of age, which were graded as light (58 g) and heavy (73 g), were placed in a commercial incubator. There were a total of 1,184 eggs distributed in four treatments and eight replicates: eggs from 27-week-old breeders (27B), eggs from 59-week-old breeders (59B), light eggs from 40-week-old breeders (40BL) and heavy eggs from 40-weekold breeders (40BH). Replicates were comprised of 37 eggs that were placed in each incubator tray. The treatments were physically separated from each other using a plate. Eggs were transferred to a hatcher after 432 hours of incubation and the first chick hatched at 449 hours of incubation. Afterwards, the number of completely hatched chicks from each replicate was recorded at six-hour intervals until 503 hours of incubation, when the hatchings stopped. Hatched chicks were removed from the trays after each measurement. Data were submitted to an analysis of variance with repeated measures. There was a significant interaction between breeder age and incubation length. The hatching onset of eggs from the old breeders was later compared to young breeders. Hatchability (%incubated eggs) was lower for the old breeders; however, differences in hatchability as a percentage of the hatched eggs were not so evident. Complete hatchability occurred only at 503 hours of incubation; however, more than 90% eggs had hatched 18 hours earlier.

The present study had the objective of investigating the performance of broilers housed immediately after hatching or after a 12 or 24 hour of post-hatching holding time. One thousand and six hundred male Ross 308 broiler chicks with an initial body weight of 46 grams were used. These chicks were distributed in a completely randomized experimental design with 5 treatments and 8 replications of 35 birds in each treatment. The treatments in this study consisted of the removal of chicks from the hatchery in three different times: after 480, 492 and 504 hours of incubation. In each one of these times, 280 chicks were removed from the hatchery and immediately housed. Another group of an identical number of chicks of each time remained in the hatchery to be housed at 504 hours after hatching. The chick group corresponding to those hatched at 480 and 492 hours performed better until 7 days. However, no differences in body weight or body weight gain were observed at the end of the study. Feed efficiency, however was worse for the birds hatched and placed at 480 hours. There were no differences among treatments for mortality

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This study investigated the hatching distribution of eggs from broiler breeders of different ages in distinct periods of incubation. Eggs were incubated in a single-stage experimental incubator. A number of 3.510 eggs were distributed into 3 treatments with 13 replicates of 90 eggs each. Treatments corresponded to breeder age: young (34 weeks), intermediate-age (44 weeks) and old (72 weeks) breeders. Eggs were transferred to the hatcher at 432 incubation hours, hatching was first checked at 449 hours, after which the number of hatched chicks was counted every 6 hours up to 515 incubation hours. After each count, hatched chicks were removed from the hatcher. Data were submitted to analysis of variance using measures repeated. A significant interaction between breeder age and incubation time was found. The total period required to hatch all incubated fertile eggs was not influenced by breeder age, which, however, affected hatching distribution. Eggs from old breeders hatched later as compared to young and intermediate-age breeders. More than 71% of the eggs had already hatched at 485 incubation hours, and 94% at 491 hours. Eggs laid by old breeders presented higher infertility and total embryo mortality, resulting in lower hatching percentage

This study aimed to evaluate broiler responses to increases in feed energy (2,870, 3,000 and 3,100 kcal ME/kg) and the inclusion of Acidulated Soybean Soapstock (ASS) when compared to Degummed Soybean Oil (DSO) in feeds from placement to 7 days of age. From 7 to 42 days ASS or DSO were included in diets that contained similar energy and nutrient levels. Metabolizable energy values used to formulate the diets for ASS and DSO were 8,351 and 7,701 kcal ME/kg in the first week and 9,314 and 8,559 kcal ME/kg afterwards, respectively. Diets were based on corn and soybean meal and were fed to 1,600 one-d-old male broiler chicks randomly placed in 40 floor pens. No differences in performance due to fat source were seen at 7 days. However, the increase in energy levels to 3,100 kcal ME/kg reduced feed intake, whereas feed conversion was improved with energy at 3,000 kcal ME/kg. Live performance, and the yields of carcass and commercial cuts were not affected by the type of fat included in the feeds from 7 to 42 days, except for increased body weight at 21 and 35 days with ASS supplementation. Litter moisture at 7, 21, 35 and 42 days was not affected by any of the factors and there were no residual effects of treatments at 21, 35 and 42 days of age. On the other hand, body weight at 35 days was affected by the interaction of diets fed in the first week with those provided afterwards. The results showed that ME values used for DSO and ASS are adequate and that ASS may be used as fat source in broiler feeds from placement to 42 days of age