Heavy Hens Research Articles

The effects of body weight and age on performance, egg quality, blood parameters, and economic production of laying hens

This study was conducted to investigate the effects of body weight on performance, egg quality, blood parameters, and economics of production of Lohmann white laying hens. A total of 288 Lohmann white layers, 44 wks of age, were allocated randomly to three groups, each formed 24 replicate cages as subgroups, comprising of four hens. The study was conducted over a period of 36 wks. Feed and water were offered ad libitum in the experiment. Performance parameters were significantly affected by body weight except for cracked egg. Considering the egg production, differences among the groups were significant (P<0.001). Egg production in the light group was higher than that of the medium and the heavy group. However, egg weight was determined to be lower in the light group (66.58 g) than in medium (67.54 g) and heavy hens (68.84 g). Hens in light body weight had lower feed intake and feed conversion ratio (FCR) than hens in heavy body weight. There were no alterations in egg quality parameters in response to increased body weight except for SS and yolk color. SS decreased linearly (P<0.001) and YC increased with BW. Other egg quality parameters did not change as BW increased. There was no change in the metabolic profile in response to increased BW except for glucose. Heavy hens had greater serum glucose concentrations than light and medium hens. This study emphasized that body weight affected the laying performance, some egg quality parameters, but had no significant effect on metabolic profile except for glucose. As a result, it was found that there was a positive relationship between the egg weight and the body weight of the hens. In this case, it is possible to produce more eggs with less feed by increasing the number of light and medium-weight chickens in the herd for profitable livestock.

Relationships between body weight and some linear morphometric traits in Nigerian Nsukka ecotype local hens


 
 
 Body weight (BW) and linear body measurements of 120 Nigerian Nsukka ecotype local hens in terms of body length (BL), chest girth (CG), thigh circumference (TC), thigh length (TL), and shank length (SL) were taken and subjected to Pearson correlation analysis to obtain the relationship between these growth traits. Multiple Linear Stepwise Regression procedure was used to find the best linear combination of the linear body measurements that can best predict BW. The findings showed that linear body measurement traits of Nigerian heavy ecotype local hens were strongly (p < 0.01) and positively correlated (0.5 < r) except thigh length which recorded a moderate value (0.3 < r > 0.5). The regression equations of linear body measurement traits with BW were positive with coefficient of determination ranging from 60.5-74.6%. The stepwise analyses showed shank length as best single measurement with R2 = 0.605, while inclusion of our five predictors in an equation resulted in R2 = 0.746. Thus, the following equation was generated: BW = – 1485.70 + 82.06 SL + 58.34 BL + 38.70 TC + 8.39 CG + 3.85 TL. This showed that they accounted for 74.6% of the variations in the BW of Nigerian heavy ecotype local hens. The prediction equations generated from linear body measurement traits are positive and strong, therefore can accurately be employed to predict the relative BW of Nigerian heavy ecotype local hens during selection programs as well as in the market with the use of measuring tape.
 
 

Keel bone fractures in Danish laying hens: Prevalence and risk factors.

Keel bone fractures (KBF) in commercial poultry production systems are a major welfare problem with possible economic consequences for the poultry industry. Recent investigations suggest that the overall situation may be worsening. Depending on the housing system, fracture prevalences exceeding 80% have been reported from different countries. No specific causes have yet been identified and this has consequently hampered risk factor identification. The objective of the current study was to investigate the prevalence of KBF in Danish layer hens and to identify risk factors in relation to KBF in all major productions systems, including parent stock production. For risk factor identification, production data from the included flocks was used. In total, 4794 birds from 40 flocks were investigated at end-of-lay. All birds were euthanized on farm and underwent inspection and palpation followed by necropsy. All observations were recorded and subsequently analysed using the SAS statistical software package. In flocks from non-caged systems, fracture prevalence in the range 53%-100%, was observed whereas the prevalence in flocks from enriched cages ranged between 50–98%. Furthermore, often multiple fractures (≥4) were observed in individual birds (range 5–81% of the birds with fractures) depending on the flock. The localization of the fractures at the distal end of the keel bone is highly consistent in all flocks (>96%). Macroscopically the fractures varied morphologically from an appearance with an almost total absence of callus, most frequently observed in caged birds, to large callus formations in and around the fracture lines, which was a typical finding in non-caged birds. Despite being housed under cage-free conditions, parent birds had significantly fewer fractures (all flocks were 60 weeks old) per bird, than other birds from cage-free systems. The body weight at end-of-lay had an effect on the risk of having fractures, heavy hens have significantly fewer fractures at end-of-lay. The older the hens were at onset of lay, the lower was the flock prevalence at end-of-lay. Additionally, the daily egg size at onset of lay was of importance for the risk of developing fractures, the production of heavier eggs initially, resulted in higher fracture prevalence at depopulation. The odds ratio of body weight, (+100 g) was 0.97, age at onset of lay (+1 week) was 0.87 and daily egg weight at onset (+1 gram) was 1.03. In conclusion, the study demonstrated a very high prevalence of KBF in hens from all production systems and identified hen size, age at onset of lay and daily egg weight at onset of lay to be major risk factors for development of KBF in the modern laying hen. Further research regarding this is warranted to strengthen the longevity and enhance the welfare of laying hens.

Body weight and range usage affect net energy utilisation in commercial free-range laying hens when evaluated in net energy chambers.

Within a given free-range flock, some hens prefer to spend the majority of their time in the shed (stayers), while others frequently access the range (rangers). Laying performance has been associated not only with the development of these sub-populations but also with different body weights (BW). The purpose of this study was to determine if range usage, BW or a combination of both is associated with energy metabolism and as such contribute to improved hen performance. Forty-eight Lohmann Brown hens at 74 wk of age were selected from a commercial free-range farm based on their BW and range usage over a 56-week period. Using a 2 × 2 factorial arrangement, hens were either classified as heavy (mean ± SEM; 2.01 ± 0.02 kg, n = 24) or light (1.68 ± 0.01 kg, n = 24), and also classified as rangers (accessed the range for 84.1% of available days, 242 ± 3.75 d; n = 24) or stayers (accessed the range for 7.17% of available days; 23.4 ± 6.08 d, n = 24). Stayers had significantly higher metabolizable energy (ME) intake per metabolic BW per d (0.852 vs. 0.798 MJ/kg BW0.75 per d; P = 0.025), higher heat production (0.637 vs. 0.607 MJ/kg BW0.75 per d; P = 0.005), higher heat increment (0.267 vs. 0.237 MJ/kg BW0.75 per d; P = 0.005) and retained more nitrogen (1.59 vs. 1.46 g/hen per d; P = 0.023) compared to the rangers. Light hens had significantly higher metabolic energy intake per metabolic BW (0.854 vs. 0.796 MJ/kg BW0.75 per d; P = 0.018), net energy (NE) intake (0.595 vs. 0.551 MJ/kg BW0.75 per d; P = 0.032), and retained energy (0.225 vs. 0.181 MJ/kg BW0.75 per d; P = 0.032), as well as lower heat production (0.936 vs. 1.003 MJ/hen per d; P = 0.002) compared to heavier hens. An interaction was observed across levels of analysis i.e. between light stayers and light rangers. The light rangers had significantly higher NE intake compared to the light stayers (9.77 vs. 9.27 MJ/kg BW0.75 per d; P = 0.024). In conclusion, light hens were more energy efficient compared to heavy hens. Moreover, light rangers had a more efficient feed utilisation compared to the light stayers.

Body weight sub-populations are associated with significant different welfare, health and egg production status in Australian commercial free-range laying hens in an aviary system

Abstract In order to assess the welfare and health status of commercial free-range laying hens of different body weight quantiles, a total of 7708 Lohmann Brown-classic hens at 74 weeks of age were obtained from 4 commercial free-range flocks housed on the same Australian farm under the same housing conditions. All hens were humanely killed and evaluated for body weight, feather cover, keel bone damage, gastrointestinal parasites, liver appearance, and egg follicle status. Hens were classified according to their body weight distribution percentile as light (bottom quartile, 1.65 ±Â 0.002 kg), medium (middle quartiles, 1.86 ±Â 0.010 kg), and heavy (top quartile, 2.08 ±Â 0.002 kg). All parameters were analysed using nominal regression models with flock, body weight, and their interactions as the predictors. In summary, 55.8% of heavy hens had a single or multiple keel bone damage compared to 48.9% and 50.7% of medium and light hens, respectively (P = 0.0001). Light hens had a significantly (P = 0.001) higher feather cover score on their breast (3.02 ±Â 0.018) than medium (2.96 ±Â 0.013) and heavy hens (2.87 ±Â 0.018) but significantly lower neck feather scores (P = 0.007). Light hens had the highest prevalence of gastrointestinal helminth infection (P = 0.0001), compared to the medium and heavy hens. Heavy hens had the highest incidence of Fatty Liver Syndrome compared to medium and light hens. Heavy and medium hens were significantly (P = 0.0001), more often in full egg follicle production (95.3% and 94.8%, respectively) compared to the lighter hens (90.0%). There was a significant flock effect for all parameters investigated. In conclusion, heavy (2.06 ±Â 0.010 kg) and medium (1.85 ±Â 0.010 kg) hens appeared healthier, more resilient towards infectious diseases and persistent in their egg follicle production. However, heavier hens suffered significantly more often from Fatty Liver Syndrome. Hens in the lowest quartile with mean 1.65 kg were the least economic sub-population.

Effect of restricted feed intake in broiler breeder hens on their stress levels and the growth and immunology of their offspring.

The prenatal environment has been shown to have significant effects on the lifelong health of offspring in humans and other species. Such effects have not been studied extensively in avian species but could prove important, especially in the case of severe feed restriction imposed on broiler breeder hens to prevent obesity and reduce rate of lay. Feed restriction can potentially affect not only nutrient supply to the embryo but stress hormone levels within the hen. This study investigated the impact of nutrient restriction of the breeder hen on growth rate and immune responses in the progeny with the objective to measure the impact of feed restriction of broiler breeder hens on growth and immune response of the progeny. Broiler breeder hens were feed restricted from 24 wk of age and maintained at three bodyweights; 3.4, 3.6, and 4.0 kg until 43 wk of age and behavioral and physiological measures of stress recorded. Chicks were hatched from each hen treatment and at day 7 vaccinated for infectious bronchitis virus (IBV) and at 16, 18, and 20 d old given an immune challenge of lipopolysaccharide. Growth and immune responses of these birds were then recorded. Sex ratio was affected by hen bodyweight, with a significantly increased proportion of males hatched from heavy hens. Growth rate from 35 to 42 d of age was reduced in male progeny from low bodyweight hens. Female progeny from heavy hens responded to an immune challenge by reduced live weight and increased heterophil: lymphocyte ratio, suggesting a more robust immune response in these birds than in the progeny from lower bodyweight hens. Overall, progeny from heavy hens had increased antibodies at day 35 to the vaccination of IBV compared with progeny of low bodyweight hens, also suggesting an improved immune response in these birds. Breeder hens restricted to the lowest feed level showed behaviors indicative of increased stress (object pecking) and an increased heterophil: lymphocyte ratio. Feed restriction of broiler breeder hens increased indices of stress in hens and resulted in offspring that have reduced growth rate and immune response in a sex-dependent way.

Effect of Corticosterone and Hen Body Mass on Primary Sex Ratio in Laying Hen (Gallus gallus), Using Unincubated Eggs1

In various studies, chronic elevation of corticosterone levels in female birds under natural or experimental conditions resulted in female biased offspring sex ratios. In chicken, one study with injected corticosterone resulted in a male sex ratio bias. In the current study, we chronically elevated blood plasma corticosterone levels through corticosterone feeding (20 mg/kg feed) for 14 days using 30 chicken hens in each of treatment and control groups and studied the primary offspring sex ratio (here defined as the proportion of male fertile eggs determined in freshly laid eggs, i.e., without egg incubation). Mean plasma corticosterone concentrations were significantly higher in the treatment group but were not associated with sex ratio, laying rate, and fertility rate. Corticosterone treatment by itself did not affect egg sex but affected sex ratio as well as laying rate and fertility rate in interaction with hen body mass. Body mass had a negative association with sex ratio, laying rate, and fertility rate per hen in the corticosterone group, but a positive association with sex ratio in untreated hens. These interactions were already seen when taking the body mass at the beginning of the experiment, indicating intrinsic differences between light and heavy hens with regard to their reaction to corticosterone treatment. The effects on laying rate, fertility rate, and sex ratio suggest that some factor related to body mass act together with corticosterone to modulate ovarian functions. We propose that corticosterone treatment in conjunction with hen body mass can interfere with meiosis, which can lead to meiotic drive and to chromosomal aberrations resulting in postponed ovulation or infertile ova.

Effect of vitamin E on reproductive performance of heavy broiler breeder hens

SUMMARY The effect of dietary vitamin E as an antioxidant and cholesterol-reducing agent was evaluated in an in vivo experiment. One hundred and eight commercial broiler breeder hens and 36 male breeders at the end of their production cycle (62–72 wk) were used as a bird sensitive to reproductive disorders related to obesity. The experimental design was a completely randomized design in a 3 × 3 factorial arrangement with 4 replicates and 3 hens in each. Factors included 3 levels of vitamin E (0, 200, and 400 mg/kg of α-tocopherol acetate added to the basal diet) and 3 groups of hens with differing BW (standard, heavy, and becoming heavy). Heavy and standard hens received a restricted amount of feed according to the strain requirement recommendations. Becoming heavy hens were fed 30% more than standard requirement. The egg production between standard, becoming heavy, and heavy groups were significantly different. The becoming heavy hen egg production was 3.1% lower than standard, and heavy hens produced 16.9% less than standard hens. Becoming heavy and heavy hens stored higher fat and cholesterol in their livers and had more yolk cholesterol and abdominal fat than standard BW hens (P < 0.05). An added 400 mg/kg of vitamin E resulted in significantly lower liver fat compared with 0 and 200 mg/kg of added vitamin E. The addition of 200 and 400 mg/kg of vitamin E to the broiler breeder hen diet reduced the fractional egg yolk weight and increased the number of white ovarian follicles significantly. Added vitamin E increased high-density lipoprotein cholesterol linearly. Feeding vitamin E at levels 4 times above that recommended by the strain management guide decreased fractional yolk weight, blood triacylglycerol concentration, and changed the metabolic direction of cholesterol in heavy broiler breeder hens.

Effects of energy concentration of the diet on productive performance and egg quality of brown egg-laying hens differing in initial body weight

The influence of AMEn concentration of the diet on productive performance and egg quality traits was studied in Hy-Line brown egg-laying hens differing in initial BW from 24 to 59 wk of age. Eight treatments were arranged factorially with 4 diets varying in energy content (2,650, 2,750, 2,850, and 2,950 kcal of AMEn/kg) and 2 initial BW of the hens (1,733 vs. 1,606 g). Each treatment was replicated 5 times (13 hens per replicate), and all diets had similar nutrient content per unit of energy. No interactions between energy content of the diet and initial BW of the hens were detected for any trait. An increase in energy concentration of the diet increased (linear, P < 0.05; quadratic P < 0.05) egg production, egg mass, energy efficiency (kcal of AMEn/g of egg), and BW gain (P < 0.05) but decreased ADFI (linear, P < 0.001) and feed conversion ratio per kilogram of eggs (linear, P < 0.01; quadratic P < 0.01). An increase in energy content of the diet reduced Haugh units and the proportion of shell in the egg (P < 0.01). Feed intake (114.6 vs. 111.1 g/hen per day), AMEn intake (321 vs. 311 kcal/hen per day), egg weight (64.2 vs. 63.0 g), and egg mass (58.5 vs. 57.0 g) were higher for the heavier than for the lighter hens (P < 0.01), but feed conversion ratio per kilogram of eggs and energy efficiency were not affected. Eggs from the heavier hens had a higher proportion of yolk and lower proportion of albumen (P < 0.01) and shell (P < 0.05) than eggs from the lighter hens. Consequently, the yolk-to-albumen ratio was higher (P < 0.001) for the heavier hens. It is concluded that brown egg-laying hens respond with increases in egg production and egg mass to increases in AMEn concentration of the diet up to 2,850 kcal/kg. Heavy hens had higher feed intake and produced heavier eggs and more egg mass than light hens. However, feed and energy efficiency were better for the lighter hens.

Bioeconomic Performance of Pullets and Layer Hens Fed Soybean Grains-Based Diets in Hot and Humid Climate

The aim of this paper was to evaluate the effects of toasted soybean grains on bioeconomic performance of pullets and layer hens in hot and humid environment. A total of 972 three-week-old Harco chicks were divided into 12 groups. At starter, pullet and laying phases, birds were fed four diets containing 0% (R0), 5% (R5), 10% (R10), and 15% (R15) of soybean grains. Results showed similar feed intake, body weight gain, laying rate, feed conversion ratio, and mortality rate between dietary treatments at each phase. The egg weight increased significantly in diet R15 (P < 0.05). The use of soybean grains reduced the feed prices. Feeding cost decreased significantly (P < 0.05) during growth and laying phases in soybean grains added diets. Feeds efficiency increased significantly (P < 0.05) with the increase of dietary soybean grains rate. Properly toasted soybean grains can be therefore included up to 15% in heavy line layer hens' diet in tropical conditions.

Transfer, viability and colonisation of Campylobacter jejuni in the chicken vitellus and in embryos

1. The objective of this study was to evaluate the ability of Campylobacter jejuni to penetrate and colonise eggs from specific-pathogen-free (SPF) and heavy breeder hens, and to determine its effects on the viability of SPF embryos. 2. We detected C. jejuni in 10% of breeder hens and 20% of SPF eggs, which demonstrates the ability of the bacteria to go through the pores of eggs and contaminate the vitellus after 3 h of contact. These results indicate that there is a risk of contamination under commercial production conditions, where, after oviposition, there is contact between the egg and organic material such as faeces and blood. 3. We observed that in 80% of SPF eggs analysed, C. jejuni survived the 21-d incubation period. This positive result suggests that this microorganism was also responsible for early embryonic mortality. 4. The ability of C. jejuni to penetrate the eggs in this study suggests that serious problems may occur under natural field conditions, which may cause significant problems for producers.

Effects of amino acids on egg number and egg mass of brown (heavy breed) and white (light breed) laying hens

Different types (light to heavy) of laying hens are used in practice. There are questions about the optimum level of balanced protein (BP) supply in feed for different types of hens. Therefore, a broad range of amino acids intake levels [550 to 800 mg of true fecal digestible (TFD) Lys/hen per d] was tested on heavy (Lohmann Brown Classic) and light (Lohmann LSL Classic) laying hens from 24 to 60 wk of age. The other indispensable amino acids were fed in fixed ratios to TFD Lys in all treatments. A total of 282 Lohmann Brown Classic and 282 Lohmann LSL Classic hens (24 wk of age) were divided into 12 experimental groups (individually housed) based on daily egg mass production and BW. Replicates of the heavy strain started with a similar average daily egg mass production (51.1 g/hen per d), laying percentage (95.9%), and hen weight (1,860 g). Replicates of the light strain started with a similar average daily egg mass production (52.0 g/hen per d), laying percentage (97.3%), and hen weight (1,478 g). Diets were fed restrictively with an aimed feed intake of 110 g/hen per day [308 kcal/hen per d of AME(n (layers))] and 100 g/hen per day [280 kcal/hen per d of AME(n (layers))] for heavy and light hens, respectively, to achieve the required BP intake levels. For light hens, a BP intake with 600 mg of TFD Lys was sufficient for optimal laying percentage, whereas maximum laying percentage was not achieved with the highest TFD Lys in heavy hens. For egg weight, daily egg mass production as well as feed conversion regression analysis revealed that asymptotes were not achieved with the highest amino acid levels in both layer strains.

Verification of Poultry Carcass Composting Research through Application during Actual Avian Influenza Outbreaks

An avian influenza outbreak in 2002 affected 197 poultry farms in Virginia and cost an estimated $130 million in losses and cleanup. In 2004-2005, researchers initiated a project to investigate the feasibility and practicality of in-house composting of turkey mortalities (heavy hens and toms) as a method of disposal and disease containment. Occurrences of low pathogenic avian influenza (LPAI) in West Virginia and Virginia in 2007 provided an opportunity for first responders to verify composting as an effective carcass disposal method. Many lessons learned from these experiences have led to improvements in the application of this technology. Market-weight turkeys, once thought too large for effective composting, were composted sufficiently for land application within 4 to 6 weeks. Additionally, fire-fighting foam, a new method of mass depopulation, proved to be compatible with composting. Knowledge gained from these incidents will be valuable not only for future responses to LPAI but also for outbreaks of highly pathogenic avian influenza such as the H5N1 virus, which currently causes disease in both animals and humans in many parts of the world. Since three-quarters of all recent emerging infectious diseases (EIDs) have arisen from animals, control of disease in animals is the principal way to reduce human exposure and prevent EIDs. Many of the general approaches and specific techniques used to eradicate the avian influenza virus can also be used to control other EIDs such as H1N1, Nipah virus, Rift Valley Fever, and plague.

Performance and profitability of second-cycle laying hens as influenced by body weight and body weight reduction during molt

An experiment was conducted to determine the effects of hen BW before molt and the percentage of BW loss during molt on the subsequent performance and profitability of hens during the second cycle of production. Results revealed that profits associated with Light hens (≤ 1,453 g, or 3.2 lb) were from 1.8¢ to 3.8¢/dozen eggs higher than those associated with Heavy hens (≥ 1,589 g, or 3.5 lb). Profits of Nonselected hens (ranging from 1,090 to 2,134 g, or 2.4 to 4.7 lb) were intermediate, ranging from 1.2¢ to 2.5¢/dozen higher than profits of Heavy hens. The increased profitability of Light hens was largely due to their improved feed conversion. Because Light hens produced predominantly Large and Extra Large eggs, the price spread between Medium and Large eggs had little impact on profits. Although not as pronounced as the effect of premolt BW, profits associated with Heavy hens that underwent a 35% reduction in BW during molt were from 0.8¢ to 1.5¢/dozen higher than those from Heavy hens with a 25% BW reduction. Reducing the BW of Light hens by 35% had no observable adverse effects in this study.

Short-Term Energy Restriction and Performance of Commercial Laying Hens

Two experiments were conducted to study the effects of various levels of feed restriction on the performance of Hy-Line W-36 hens at 56 and 79 wk. Nutrient levels (with the exception of energy) increased as the level of feed restriction increased. Egg weights were not affected by any level of feed restriction in either experiment. Egg production decreased in Experiment 1 when he3ns received 86.3g of fee/day or less. Egg production decreased in Experiment 2 by 2 wk when feed was restricted to 76 g/bird/day and also by 2 wk when hens were fed 67 g/hen/day. Body weight loss increased with each level of feed restriction in both experiments. In Experiment 1, heavy hens lost the most weight and light hens the least.

Ornithobacterium rhinotracheale Infection in Turkey Breeders

A sequence of outbreaks of respiratory disease separated by intervals of about 2 wk occurred on three turkey breeder ranches. The last two ranches affected belonged to different companies and were separated by a distance of 11 km. Mortality on the last ranch was particularly severe among certain segregated groups of turkeys that included toms, heavier birds, and birds undergoing a stressful event such as artificial insemination. On this ranch, percentages of mortality within an 18-day period were 5.2% in toms, 2.4% in hens, 7.4% in heavy toms and 5.4% in heavy hens. Turkeys from 27 to 42 wk of age were examined during the outbreaks. Gross lesions included severe lung consolidation with fibrinous exudate on the pleura and air sacs, petechiae on the epicardium, and increased cloudy fluid in the pericardial sac. Liver and spleen were moderately enlarged. Histologically, there was severe fibrinoheterophilic inflammation in the airways, pleura, and air sacs and severe perivascular interstitial edema in the lungs. Liver had acute coagulative necrosis of hepatocytes associated with occasional thrombosis at the periphery of the liver lobes. Ornithobacterium rhinotracheale was isolated from tissues of the respiratory system, such as infraorbital sinus, trachea, lung, and air sacs, but not from the liver, spleen, or bone marrow. Escherichia coli was isolated less often from lung, air sac, and trachea.

Effect of Feed Regimes on Body Weight of Turkey Hens at 32 Weeks of Age and Subsequent Reproductive Performance

Large Broad Breasted White turkey hens were fed ad libitum or on a restricted basis to determine the optimum body weight for housing turkey hens at 32 weeks of age. At 32 weeks of age there was no significant difference (P < .05) in body weight of hens fed ad libitum (8.3 kg.) and those fed ad libitum to 20 weeks of age (8.3 kg.) and then fed a feed with less nutrient density. Hens fed 80% of the calculated normal intake weighed significantly more (7.4 kg.) at 20 weeks of age than birds fed three days per week for an eight hour period (6.7 kg.), but there was no significant difference (P < .05) at 32 weeks of age.To evaluate the effect of body weight at 32 weeks of age on subsequent performance, pens of hens were classified into three weight groups. Hens weighing less than 7.05 kg. were classified lightweight; above 8.41 kg. were heavy; with those between classified intermediate. There was no significant difference (P < .05) in fertility, hatch of fertile eggs, hatch of all eggs, or average egg weight based on body weight. Intermediate weight hens produced significantly more eggs (P < .05) than the lightweight or heavy hens.

Effect of Type, Age, and Freezing of Poultry Meat Before Processing on the Quality of Chicken Frankfurters

AT THE present time there is a tremendous amount of interest in combining poultry meat with other meats in emulsion type meat products. In this regard, the relative merits of various ages and types of poultry in frankfurters is of concern. Considerable work has been done in recent years to determine the effect of type, age and part of poultry meat on its emulsifying ability (Maurer et al., 1966, 1969; Hudspeth et al., 1967, 1969). While fat emulsification no doubt plays a large role in the formation of a good sausage emulsion and subsequently a good finished product, other factors may also be important.This study was undertaken to evaluate the relative effectiveness of meat from fryers, hens and turkeys in making frankfurters. The effect of freezing the meat prior to processing was also determined.MATERIALS AND METHODSExperiment 1. Effect of type and age. Heavy hens (Cornish × White…

Essential Amino Acid Composition of Chicken Meat and Drip After 30 and 90 Days of Frozen Storage

SUMMARY– Light and dark meat from 24 heavy hens was frozen and stored for 30 and 90 days. After storage, drip was collected and moisture and fat removed. The essential amino acids in acid and alkaline hydrolyzates of dark and light chicken meat and drip were determined by microbiological assay. Acid hydrolyzates from drip were also analyzed on a Beckman/Spinco Amino Acid Analyzer. The concentration of amino acids in both dark and light meat decreased and the concentration in drip increased with increasing storage time. In addition, larger quantities of essential amino acids were detected in drip from frozen light meat than from frozen dark meat after both periods of storage. The quantitative results obtained from the analyzer were in general agreement with those obtained by microbiological assay but were somewhat higher. The concentration of each amino acid, as a percentage of total amino acids, was similar in meat and drip.

Chicken Flavor: the Identification of Some Chemical Components and the Importance of Sulfur Compounds in the Cooked Volatile Fraction

SUMMARYMeat and water slurries of both leg and breast muscle from heavy hens were cooked in a nitrogen atmosphere. Some of the chemical components in the volatile fraction were identified by solubility classification, derivative preparation, and/or functional group analysis in combination with gas chromatography and/or qualitative chemical analyses and odor evaluation. Twenty‐nine compounds in the volatiles from leg muscle and 25 compounds from breast muscle were identified by the functional‐group trapping technique followed by gas chromatography of the effluent fractions. Qualitative chemical tests revealed 19 major classes of compounds and a few specific compounds.Removal of sulfur compounds resulted in an almost complete loss of “meaty odor” in both dark and light meat. Removal of the carbonyls from the volatile fraction resulted in a loss of “chickeny‐flavor” and intensification of the “meaty or beef‐like odor.”