Heavier Egg Weight Research Articles

Performance of Egg Laying Japanese Quail Hens Fed Low Protein Diet Supplemented with Protease and/or Formic Acid

This study aimed to decrease the cost of laying rations by lowering protein as it’s the most expensive constituent in the diet. So, the research stated to investigate the effect of incorporating protease and/or formic acid as feed additives into a low protein isocaloric diet of laying Japanese quail hens on the productive performance, some egg quality parameters and economic efficiency. It was performed on 120 of 5–6-week-old healthy Japanese quail hens (weighed 268g7.06±) and randomly distributed into five groups (3 replicates per group). G1 (control with basal layer quail diet 20% protein), G2 (17% protein diet without protease enzyme or formic acid), G3 (17% protein diet + 0.05% protease enzyme), G4 (17% protein diet + 0.5% formic acid), G5 (17% protein diet + 0.05% protease enzyme + 0.5% formic acid). The experimental period lasted for 12 weeks with two weeks of adaptation before this period. For each replicate, daily egg number, daily egg weight, and egg mass as well as weekly feed intake were recorded. At the end of each week, eggs were collected from each replicate to evaluate egg quality. Mean egg production, egg albumin %, eggshell % and egg yolk % in all groups do not differ significantly with control but G2 was numerically higher than control in egg production, egg mass, FCR, egg shell %, egg yolk % and feed intake. G2 significantly has the heavier egg weight among groups (p < 0.05) as the average egg weights were 11.77g and 12.48g in control and G2 respectively. G3 was being the highest in feed intake and egg albumin percent than the other groups. G4 was being the highest in eggshell percent. Triglycerides per the whole yolk were lower in all groups than in the control. Cholesterol (mg)/whole yolk was low in G2 and G3. FCR was improved in G5. G2 had the highest net revenue and economic efficiency (48 LE&114.3%) in compare with control (46 LE&106.98%), while the values were 47.1LE&107.3%, 43.3LE&101.4% and 46.2 LE&105.5% for groups G3, G4 and G5 respectively. It could be concluded that feeding laying Japanese quail hens on diet containing 17% protein without protease enzyme or formic acid did not differ significantly from those fed on a control diet containing 20% protein. Moreover, it showed the highest net revenue and numerical improvement than the control group regarding egg production, egg mass, FCR, eggshell %, egg yolk %, and cholesterol in egg yolk.

Research Note: Growth promoting potential in Mstn mutant quail dependent and independent of increased egg size

In avian species, positive relationships between egg weight (EW) and body weight (BW) have been reported. However, the correlation between the body growth rate and different weights of eggs from genetically mutated avian species was not studied yet. Myostatin (Mstn), an anti-myogenic factor, mutant quail were recently developed, and it was reported that EW produced from Mstn homozygous mutant quail (HO) was heavier compared to those from wild-type quail (WT). In the current study, distributions of pre-incubated EW and associations between EW and BW were compared between the Mstn mutant and WT quail lines. Average egg weight for the HO group was significantly heavier than the WT (P < 0.001) and the number of eggs having heavier EW (over 11 g) was higher in the HO compared to the WT (P < 0.01). BWs at wk (W) 0, 4, and 6 after hatch were also significantly greater in the HO (P < 0.001 in all groups). In addition, linear regression analyses revealed positive relationships between EW and BW from W0 to W6, regardless of sexes and genotypes. Furthermore, Mstn mutant quail were a heavier BW compared to the WT quail originated from eggs with similar weights. These data indicate that increased BW by Mstn mutation is contributed by increased EW and/or growth promoting activity of Mstn mutation independent of increasing egg sizes. These findings provide Mstn as a desirable genetic factor for selection of poultry breeds with superior growth. In addition, the knowledge gained from this study could inspire similar proof-of-concept studies involving standard and commercial lines of poultry.

Dietary supplementation of spirulina and canthaxanthin boosts laying performance, lipid profile in blood and egg yolk, hatchability, and semen quality of chickens.

This study examined the impacts of dietary spirulina (SP) and canthaxanthin (CX) supplementation to laying hens on reproductive performance and cock's semen quality evaluation. Three hundred and sixty of indigenous Sinai chickens (300 hens + 60 cocks), 48-weeks-old, were randomly divided into five treatments; a control and four supplemented (0.6 g SP mg/kg, 0.8 g SP mg/kg, 6 mg CX/kg diet, and 8 mg CX/kg diet) with six replications of 10 females and 1 male per treatment for laying trial and 1 male for semen evaluation. The animals were fed with experimental diets for 12 weeks. Supplementing 6 mg CX/kg diet led to an increase in the final body weight and egg production traits, while 8 mg CX/kg diet resulted in an improving feed conversion ratio. Supplementation of 0.6 g SP mg/kg or 6.0 mg CX/kg diet resulted in the highest egg production. The heaviest egg weight and egg mass were induced by 0.8 g SP mg/kg. Eggs laid from hens fed 0.6 g SP/kg diet had a higher concentration of cholesterol than those fed 0.8 g SP/kg and those fed 6.0 and 8.0 mg CX/kg. Cocks fed 6 mg CX/kg and those fed 0.8 g SP/kg diet had the greatest sperm concentration. The supplementation of 0.8 g SP mg/kg diet or both 6 and 8 mg CX/kg diet enhanced hatchability. So, dietary spirulina (0.8 mg/kg) and canthaxanthin (6 mg/kg) supplementation to Sinai laying hens and cocks could be used to improve productive and reproductive and performance.

IMPACT OF GROWTH HORMONE GENE TRANSFER BY SPERM-MEDIATED GENE TRANSFER ON EGG PRODUCTIVE AND REPRODUCTIVE TRAITS OF BANDARAH LOCAL CHICKEN

The experimental was aimed to improve genetic of Bandarah Local chicken strain to insert Growth hormone gene (cGH) from (Cobb 500) broiler strain by method sperm-mediated gene transfer technique (SMGT). This study investigated for two generations. Total RNA was extracted from chicken liver tissue and the cDNA was successfully prepared. PCR Products GH, mRNA normal Length 810bp for transgenic Bandarah chickens which treated by SMGT method, the same result was found in the first and second generation. The averages of fertility percentage were 88.97% and 92.14 % for SMGT and control, respectively. The overall mean of the second generation was nearly value 90.76% of the first one 90.38%.The responses of the transgenic techniques SMGT for fertility percentage were 5.64%. The responses of hatchability for SMGT were 18.35% and 21.82% for fertile and total eggs, respectively The SMGT of transferring was decreased the age at sexual maturity ASM at the second generation by 35.01 d. Egg number which produced during the first 90 days from SMGT method significantly increased compared by the control. There was highly significant difference between treated found, the SMGT method had the heaviest egg weight 49.20 g followed by control one 48.22 g. After two generations, the SMGT technique was improved egg number by 10.62 egg, decreased egg weight by 0.9g and improved egg mass during the first 90 days of laying by 512.62 g. SMGT is an efficient method that will hopefully facilitate the implementation of strategies for securing the benefits that can be expected to arise from the introduction of transgenic chicken. Chicken cGH gene was affected in egg productive traits and reproductive traits and moved from the first generation to the second generation with the same shape and increased the effect. Growth hormone gene transfer by SMGT will save time to improve egg productive traits and reproductive traits.

EFFECTS OF DIETARY TURMERIC AND FENUGREEK POWDER SUPPLEMENTATION ON PRODUCTIVE PERFORMANCE OF LOCAL LAYING HENS

This experiment was performed to study the effect of adding turmeric(TU) or fenugreek seeds (FE) and both of them in laying hen diets on productive performance. A total number of 90 hens of Sinai local strains, at 59-wks-old were used, weighed individually and allotted randomly into six experimental groups, with three equal replicates, five hens each. Hens had almost similar of initial average live body weights. The 6 treatments were: control treatment (T1) fed on basal diet. The second treatment (T2) was fed on basal diet with 0.1 % turmeric powder. While third and fourth treatments (T3 and T4) supplemented with fenugreek seeds powder levels 0.1 or 0.2 % , respectively. Then, the fifth and sixth treatments (T5 and T6) were given turmeric at level 0.1 % plus 0.1 % or 0.2 % fenugreek seeds, respectively. The results showed that hen group fed on a diet supplemented with 0.1 % TU + 0.2 % FE (T6) achieved the best records of average egg numbers produced per hen and total egg number (60.3). Also, the same treatment attained higher laying rate and egg mass among experimental periods for overall period. Fenugreek seeds alone or with turmeric (T3, T4 and, T5) had positive effects on average egg weight, the heavier egg weight (53.7 g) for T4 during 71-74 wks of age compared with 50.6 g for the control treatment. Feed intake during the overall period was not significantly affected by studied feed additives. Meanwhile, T6 obtained the best FCR as compared with other treatments. Shell index, yolk index and albumin % did not significantly affect by feed supplements. There was improvement in yolk %, shell %, shell thickness and Haugh units due to evaluated additives in hen layer diets. Hens fed on diet with 0.1 % TU + 0.2 % FE (T6) recorded the highest net return and economic efficiency compared to other treatments. In conclusion, the results elucidate that adding turmeric, fenugreek or combination of them enhanced egg production, FCR and egg quality. Also, economic efficiency was improved by adding the mixture of the additives to elderly Sinai local hen diets at the late stage of productive age, 59 – 74 weeks of age.

Effect of Magnetic Water on Semen Evaluation and Some Hatchability Traits for Egyptian Developed Chickens

A total of 280 females with 28 males for Silver Sabahia strain at two different ages (35 and 50 weeks) were used in this study. Besides, 40 cocks (10 cocks / group) used for semen evaluation. Birds of each age were divided into two groups, the 1st group drank water exposed to magnetic field (MFW) and the 2nd group drank non-magnetic tap water (TW) to determine the beneficial effect of drinking magnetized water for aged chickens to cope low fertility% and hatchability%, besides studying semen and egg parameters, embryonic development and chick quality. Supplementation elder cocks with MFW significantly increased semen volume, number of motile sperm and number of live sperm compared with those for untreated cocks. Treated old flock with magnetic water had a heavier egg weight (p≤0.05) than treated young flock with magnetic water. MFW X old and MFW X young had a comparable influence on egg weight loss, embryonic mortality, fertility% and hatchability%. On day 14 and 18 of incubation, supplementation older birds with MFW water had a heavier residual yolk sac weight% compared with the other rest groups. At hatch, the residual yolk sac weight% was similar between MFW X old and MFW X young. In addition, chick weight and all internal organs weight% were not affected by interaction of both types of water and hens age. It is concluded that exposing water to magnetic field, have a stimulating influence on the percentages of fertility and hatchability of birds (especially older age) through improving semen and egg qualities, besides stimulating the development of embryogenesis.

EFFECTS OF DIETARY TURMERIC AND HOT PEPPER POWDER SUPPLEMENTATION ON PRODUCTIVE PERFORMANCE OF LOCAL LAYING HENS

This experiment was performed to study the effect of adding turmeric(TU) or fenugreek seeds (FE) and both of them in laying hen diets on productive performance. A total number of 90 hens of Sinai local strains, at 59-wks-old were used, weighed individually and allotted randomly into six experimental groups, with three equal replicates, five hens each. Hens had almost similar of initial average live body weights. The 6 treatments were: control treatment (T1) fed on basal diet. The second treatment (T2) was fed on basal diet with 0.1 % turmeric powder. While third and fourth treatments (T3 and T4) supplemented with fenugreek seeds powder levels 0.1 or 0.2 % , respectively. Then, the fifth and sixth treatments (T5 and T6) were given turmeric at level 0.1 % plus 0.1 % or 0.2 % fenugreek seeds, respectively. The results showed that hen group fed on a diet supplemented with 0.1 % TU + 0.2 % FE (T6) achieved the best records of average egg numbers produced per hen and total egg number (60.3). Also, the same treatment attained higher laying rate and egg mass among experimental periods for overall period. Fenugreek seeds alone or with turmeric (T3, T4 and, T5) had positive effects on average egg weight, the heavier egg weight (53.7 g) for T4 during 71-74 wks of age compared with 50.6 g for the control treatment. Feed intake during the overall period was not significantly affected by studied feed additives. Meanwhile, T6 obtained the best FCR as compared with other treatments. Shell index, yolk index and albumin % did not significantly affect by feed supplements. There was improvement in yolk %, shell %, shell thickness and Haugh units due to evaluated additives in hen layer diets. Hens fed on diet with 0.1 % TU + 0.2 % FE (T6) recorded the highest net return and economic efficiency compared to other treatments. In conclusion, the results elucidate that adding turmeric, fenugreek or combination of them enhanced egg production, FCR and egg quality. Also, economic efficiency was improved by adding the mixture of the additives to elderly Sinai local hen diets at the late stage of productive age, 59 – 74 weeks of age.

Combination Effect of Golden Snail Powder and Fermented Coconut Cake on Quality of Duck Eggs

This study aims to determinate the effect of combination golden snail powder and fermented coconut cake on quality of duck eggs. We were using experimental feeds combination form golden snail powder and fermented coconut cake as raw material for livestock rearing for duck. This research was conducted in July - September 2018 in Mangkoso Village, Barru Regency and continued with sample testing at the Laboratory Animal Husbandry Faculty of Livestock Product Technology University of Hasanuddin. This study used 16 female duck who are 20 weeks old with four types of treatments consists of four replications of each treatment. The egg quality was carried out using a sample of 16 eggs from Ducks which was maintained and treated with different rations. The data obtained were analyzed using variance analysis with a Completely Randomized test for significant different results. The results of the combination of golden snail powder and fermented coconut cake on egg color, egg white index, egg yolk index, haugh unit (HU) value of egg units. All treatments (P1, P2, P3) gave effect to three parameters, namely eggshell quality, egg yolk index and egg yolk color, while the other three parameters namely egg weight, egg white index and Haugh Unit (HU) value did not differ significantly from negative controls. The best treatment was shown by treatment P3 which gave an effect on the heavier egg weight than other treatments, eggshell quality grade A, Egg White Index and Egg Yolk Index showed good quality and bright golden egg yolks.

Does light intensity affect the behavior, welfare, performance, meat quality, amino acid profile, and egg quality of Japanese quails?

The current study aimed to explore the impact of different light intensities on behavior, welfare, performance, meat quality, amino acid content, and egg quality of Japanese quails. A total of 600 1-day-old Japanese quail chicks were used (300/batch). Chicks were homogeneously classified into 3 groups (each of 100); low (10 lux), moderate (50 lux). and high light intensity (250 lux) groups. There was a significant effect (P < 0.05) of light intensity in most of the Japanese quails' behaviors. Quails reared on low light intensity showed the lowest behavior of feeding, drinking, flying, and feather picking, while the highest behaviors were preening, dust bathing, leg and wing stretching, and body shaking when compared with the other groups. Moreover, they had the better welfare (lowest H/L ratio and corticosterone levels). Quails of low light intensity groups possessed the heaviest body weight (145.17g, P = 0.000) with the lowest daily feed intake (14.17g) but with the best feed conversion ratio (3.39%, P = 0.000). Moreover, they had the heaviest slaughter (132.47g, P = 0.000) and carcass weight (109.29g, P = 0.000) and carcass yield (75.37%, P = 0.000) when compared with the others groups. Muscles of quails (both of pectoral and thigh) kept under low light intensity revealed the highest percentage of lightness, yellowness, and water-holding capacity with the lowest percentage of cooking loss, thiobarbituric acid reactive substances, and some amino acids. They also had the heaviest egg weight (11.24g, P = 0.000) with the best external and internal egg-quality grades (P < 0.05). Consequently, low light intensity is suggested for improving quail's welfare, performance, and reproduction, while the high light intensity had a detrimental effect on both welfare and performance.

Roles of the sire and dam quail in egg, yolk, albumen, and shell weight alterations due to the parthenogenetic trait

Infertile eggs from Chinese Painted quail exhibit parthenogenesis, and the 1st egg in a clutch sequence is more likely to develop a parthenogenetic embryo. Also, hens that exhibit parthenogenesis have shorter clutches and heavier egg weights. These larger eggs may be a result of the egg residing in the oviduct longer, allowing more time for the parthenote to develop. However, it is unknown which components of the egg are altered due to the parthenogenetic trait or the role of dams and sires from the parthenogenetic line of quails in these alterations. Therefore, our objective was to determine if the parthenogenetic trait in dams, sires, or both contributes to alterations in egg components, such as yolk, albumen, and shell weights. Two selected lines of quail, 1 line selected for parthenogenesis and 1 line that was unselected for the parthenogenetic trait (control), were utilized in a 2 x 2 factorial arrangement of dam and sire lines to create 4 breeding treatments: control dams + control sires (CC), control dams + parthenogenetic sires (CP), parthenogenetic dams + control sires (PC), parthenogenetic dams + parthenogenetic sires (PP). Daily, fresh eggs were collected, labeled, weighed, and the germinal disc was classified as fertile, unfertilized without development, or parthenote. Yolk, albumen, and shell weights were obtained, and their weights were also calculated as percentage of total egg weight. A dam main effect revealed heavier weights for total egg, yolk, albumen, and shell as well as a larger percentage of albumen and ratio of albumen to yolk in parthenogenetic line dams versus control line dams. However, the percentage of yolk was higher for control than parthenogenetic line dams. The increase in total egg and egg component weights due to the parthenogenetic trait suggests that the transit time of the egg through the oviduct is altered. Perhaps transit through the magnum and uterus is delayed the most yielding greater albumen and shell weights, respectively.

Effect of dietary supplementation of butyric acid glycerides on performance, immunological responses, ileal microflora, and nutrient digestibility in laying hens fed different basal diets

A total of 150 laying hens (55-wk-old) were used to investigate the effect of different levels of butyric acid glycerides (BAG) on performance, egg quality, ileal microbial populations, and nutrient digestibility in hens fed different basal diets. Dietary treatments consisted of 2 different basal diets (corn- or wheat-based diets) and 3 supplemental BAG levels (0, 2.5, and 5.0g/kg) in a 2×3 factorial arrangement with 5 replicate cages and 5 hens per cage. The study lasted for 77d, including 7d for adaptation and 70d as the main experimental period. In addition to performance variables, antibody responses to different antigens were assessed after the inoculation. Furthermore, ileal digesta was collected from 3 euthanized hens per replicate at the end of the study to determine microbial count and ileal nutrient digestibility. Results showed that dietary BAG supplementation (2.5 and 5.0g/kg) increased egg production and egg mass, but it had more impact in hens fed wheat-based diets (basal diet×BAG, P<0.05). Dietary supplementation of BAG increased both egg production and egg mass, but those response criteria were greater with 5.0g/kg compared with 2.5g/kg. The heavier egg weights were observed for the hens fed corn-based diets (P=0.001), however, feed intake was not influenced by dietary treatments. Supplemental BAG (2.5 and 5.0g/kg) improved feed conversion ratio and it was lower in hens fed 5.0g/kg than those fed 2.5g/kg of BAG, especially in those hens fed the wheat-based diets (basal diet×BAG, P=0.022). Yolk color index was greater (P<0.001) in eggs produced by hens fed on corn-based diets. In contrast to Newcastle antibody titer, dietary inclusion of BAG (2.5 and 5.0g/kg) increased (P=0.011) antibody response against sheep red blood cell during primary response. Serum concentrations of triglycerides and cholesterol were lower (P<0.01) in hens fed wheat-based diets, and they increased (P<0.01) as supplemental BAG level was increased. Total bacterial count and Escherichia coli (E. coli) population were greater (P<0.05) when hens were fed wheat-based diets, and dietary BAG supplementation (2.5 and 5.0g/kg) reduced (P<0.05) total bacteria and ileal E. coli enumerations. Supplemental BAG (2.5 and 5.0g/kg) increased digestibility coefficients of ether extract (P=0.009) and also total ash, even though there was the interaction on total ash (P=0.045). The present findings indicate that BAG supplementation of diets could increase production performance of laying hens, probably because of the decreased intestinal E. coli count, and this effect was more obvious in wheat-based diets.

Desempenho de codornas de corte oriundas de diferentes classes de idades da matriz e de peso dos ovos

Estudou-se o efeito interação idade da matriz versus peso do ovo sobre o desempenho produtivo de codornas de corte (Coturnix coturnix coturnix) no 21º e 42º dias de idade. Em cada classe de idade da matriz, iniciada a partir de 70, 205 e 280 dias, foram incubados 600 ovos, separados em três categorias de peso: categoria 1 − ovos com 11,0-12,9g; categoria 2 − ovos com 13,0-14,9g; e categoria 3 − ovos com 15,0-16,9g. Após a eclosão, em cada idade da matriz, foram utilizadas 225 codornas de um dia, de ambos os sexos, provenientes das três categorias de peso, sendo 75 codornas por categoria. O delineamento experimental foi inteiramente ao acaso, com os tratamentos consistindo de um fatorial 3x3, ou seja, três classes de idades da matriz x três categorias de peso do ovo, com cinco repetições de 15 codornas por unidade experimental. A dieta experimental foi única para todos os tratamentos com 28% de proteína bruta e 2900kcal de energia metabolizável. O desempenho das codornas foi avaliado por meio das variáveis ganho de peso (g), peso corporal (g), consumo da dieta (g/ave) e conversão alimentar (g de dieta/g de peso) no 21º e 42º dias de idade. Não houve interação significativa entre idade da matriz e categoria de peso do ovo sobre as características de desempenho das codornas. Codornas oriundas de ovos mais pesados e de matrizes das classes 205 e 280 dias de idade apresentaram maiores desempenhos. No 42º dia de idade das codornas, não houve diferença para categoria de peso do ovo. Ovos mais pesados originaram codornas mais pesadas ao nascimento.

Efeito da interação idade da matriz x peso do ovo sobre o desempenho de codornas de corte

Avaliou-se a interação idade da matriz versus peso do ovo sobre o desempenho produtivo de codornas de corte (Coturnix coturnix coturnix) no 21º e 42º dias de idade. Em cada classe de idade da matriz, iniciada a partir de 70, 205 e 280 dias, foram incubados 600 ovos, separados em três categorias de peso: categoria 1 - ovos com 11,0-12,9g; categoria 2 - ovos com 13,0-14,9g e categoria 3 - ovos com 15,0-16,9g. Após a eclosão, em cada idade da matriz, foram utilizadas 225 codornas de um dia, de ambos os sexos, provenientes das três categorias de peso, sendo 75 codornas por categoria. O delineamento experimental foi inteiramente ao acaso, e os tratamentos consistiram das três classes de idades da matriz x três categorias de peso do ovo, com cinco repetições de 15 codornas. A dieta experimental foi única para todos os tratamentos com 28% proteína bruta e 2900kcal de energia metabolizável. A categoria peso do ovo e a classe de idade da matriz influenciaram o peso corporal, o ganho de peso e o consumo da dieta no 21º e 42º dias de idade. Codornas oriundas de ovos mais pesados e de matrizes das classes de 205 e 280 dias de idade apresentaram melhor desempenho (P&lt;0,05). A viabilidade foi influenciada pela categoria peso do ovo, ou seja, codornas provenientes de ovos mais leves apresentaram menor viabilidade aos 21º e 42º dias de idade (P&lt;0,05). Ovos mais pesados originaram codornas mais pesadas ao nascimento (P&lt;0,05).

Reproductive Performance of the Ardennaise Chicken Breed under Traditional and Modern Breeding Management Systems

Enhancing the use of traditional chicken breeds is necessary to insure long-term conservation of global genetic diversity in poultry. A logical start in this process is to evaluate performance. The objective of this study was to estimate reproductive traits in the Ardennaise chicken breed under traditional and modern management systems. Reproductive performance indicated lighting programs (Natural (NAT) or Artificia l (ART) day length) were highly significant for egg weight, hatchability (p 27 weeks), utmost maximum production peak (56.67%), largest egg number (70.13 eggs/hen) and number of chicks hatched (24.10 chicks/hen) were performed under ART-AL. Heaviest egg weight (53.21g), highest fertility (70.20%), greatest hatchability (55.58%), highest liveability during rearing (95.74%) and lay (100%), lowest early (3.51%) and mid-term embryonic mortality (1.17%) were achieved under NAT-AL. To summarize, most of traits studied in the Ardennaise chicken were moderate when compared to those expected by broiler breeders.

Further Studies of Density and Group Size Effects in Caged Hens of Stocks Differing in Fearful Behavior: Productivity and Behavior ,

Two experiments were done involving moderately inbred strains known to differ in escape and avoidance behavior. Hens of those strains and of a cross between them (second experiment only) were compared for fear-related behavior, feather damage and loss, and productivity traits when housed four or eight/cage at densities of 348 (high), 464 (medium), and 580 (low) cm2/bird. Hens that died were replaced. Strain cross hens did not differ from parental strain hens in nervousness, feathering scores, or survival, but exhibited hybrid vigor for rate of lay, egg weight, daily egg mass, and age at sexual maturity.Density, but not group size, affected rate of lay, daily egg mass, and percentage survival. Hens in high density cages were adversely affected but those in medium and low density cages did not differ from each other. Nervousness and feather loss were influenced adversely and stepwise by higher densities, and hens in cages of eight were more nervous and had greater feather loss and damage than those in low density cages.There were no interactions between stock and density or group size for any of the traits measured. However, there was an interaction of stock with age period for both egg weight and daily egg mass. Strain cross hens had an advantage over parental hens during the earlier part of the laying year because of their earlier maturity and relatively heavier egg weights during that period.There was an interaction between density and group size for rate of lay and egg mass during the second and larger scale experiment only; hens in eight-bird cages performed at lower levels than did hens in four-bird cages only when kept at high density. There was a strong interaction between density, but not group size, and age; adverse effects of the high-density cage environment became more evident as time passed.