Egg production and egg quality in free-range laying hens housed at different outdoor stocking densities

Effects of different stocking densities on the development of reproductive and immune functions in young breeder pigeons during the rearing period

1. Stocking density (SD) is closely related to animal performance. This experiment was designed to evaluate the development of reproductive and immune functions of young pigeons under different SDs.2. A total of 288 (half male and half female) 40-day-old pigeons (body weight 400 ± 15 g) were allocated into four groups: High stocking density (HSD; 0.308 m3/bird), standard stocking density (SD; 0.616 m3/bird), and low stocking density (LSD; 1.232 m3/bird) and a caged (control; 0.04125 m3/bird). Every group had six replicates of the same sex.3. The results showed that caged male pigeons had the highest testis index, testosterone content, and gene expression of the androgen receptor gene. LSD treatment induced the highest concentrations of oestradiol, progesterone and mRNA levels of reproductive hormone receptor genes in female pigeons. In male pigeons, the spleen index (organ weight calculated as a percentage of total body weight) showed a peak level (0.09 ± 0.020) in the LSD group, and the thymus index peaked (0.23 ± 0.039) in SD group. However, the index for ovary, spleen, thymus and bursa of Fabricius in female pigeons showed no significant changes among different groups.4. The IL-1β, IL-8, IFN-γ, TGF-β and toll-like receptor 2 (TLR-2) mRNA levels reached their maximum values in both male and female pigeon spleens in the LSD group.5. Young male pigeons housed in cages showed increased testicular development while low stocking density increased the development of reproductive function in young female pigeons. A larger activity space could help enhance the immune function of both male and female pigeons.

Influence of Genotype on Productivity and Egg Quality of Three Hen Strains Included in a Biodiversity Program

The aim of the study was to evaluate the effect of genotype on the productivity and egg quality of three hen strains included in the genetic resource protection program in Poland. The study encompassed populations of laying hens, i.e., Rhode Island Red/RIR (R-11 and K-22) and Rhode Island White (A-33). The analysis over five generations included the basic production traits, i.e., the weight of the birds at 20 weeks (g), egg weights at 33 and 53 weeks, sexual maturity, the number of eggs laid up to 56 weeks of age, and hatchability parameters. In addition, the effective population size (Ne) and flock homozygosity coefficient (Fx) were calculated for each breed. Population health during the rearing and production periods was also recorded. The study also determined egg content and shell quality traits in relation to the age of the hens. The birds were kept on litter at a stocking rate of 5 hens/m2 and fed ad libitum with a standard feed mixture for hens. Based on the results, it was concluded that the evaluated hen populations (R-11, K-22, and A-33) are valuable strains, representing a reservoir of unique phenotypic and egg quality traits. It was shown that the random mating system used in the reproduction of flocks effectively protects the populations from an increase in the degree of inbreeding. An influence of hens' origin (genotype) and age on the performance results, as well as egg quality traits, was found. Over five generations, the evaluated hen strains were characterized by high survival rates (above 98%). The study also found a large variation between the R-11 and K-22 strains and the A-33 strain in terms of the evaluated performance traits, especially in the body and egg weights, sexual maturity age, and laying performance of hens. The earliest to start laying were hens from the K-22 strains, which also showed significantly (p ≤ 0.05) higher laying performances compared to R-11 hens. The results also indicate that the quality of eggs from hens of the compared strains varied. This was particularly true for such traits as shell color; egg, shell, and yolk weight; and shell quality. It was also shown that many egg and shell quality traits change with the age of the hens. The analysis of the obtained data indicates that the adopted methods of conservative breeding for these populations have influenced the success of the conservation program.

The Potential of Understory Production Systems to Improve Laying Hen Welfare

Simple Summary

Non-cage farming is gradually becoming the mainstream mode of poultry farming worldwide, which has led to concerns regarding the welfare of laying hens in China. Under huge pressure for the supply of eggs, China, with relatively insufficient land resources, is highly dependent on cage systems, thus posing significant challenges related to animal welfare. In the context of this dilemma, China’s abundant woodland resources provide a means to improve the welfare of laying hens, in particular, providing a wide living space for laying hens to express their natural behaviours, such as foraging and reproduction. At the same time, this profitable farming model has been welcomed and supported by farmers in some areas of China, and is gradually being promoted, which may provide a template and confidence for China and other countries to address the challenges of keeping hens in non-cage systems in order to improve animal welfare.

Abstract

The welfare of laying hens in cage systems is of increasing concern. Represented by the European Union’s ‘End the Cage Age’ initiative, more and more countries have advocated cage-free farming. China, an important country for poultry farming and consumption in the world, is highly dependent on cage systems and lacks confidence in alternative (e.g., free-range) systems. In this context, using China’s abundant woodland resources (including natural forests, plantations, and commercial forests) to facilitate the management of laying hens in a free-range environment may provide highly promising welfare improvement programs. On the basis of the Five Freedoms, we assess the welfare status of understory laying hen management systems with reference to the behavioural needs and preferences of laying hens and the EU standards for free-range and organic production (highest animal welfare standards in the world). The results show that the considered systems meet or even exceed these standards, in terms of key indicators such as outdoor and indoor stocking density, outdoor activity time, and food and drug use. Specifically, the systems provide sufficient organic food for laying hens without using antibiotics. They allow laying hens to avoid beak trimming, as well as to express nesting, foraging, perching, reproductive, dustbathing and other priority behaviours. The presence of roosters and higher use of woodland space allow the laying hens to achieve better feather and bone conditions, thus reducing stress and fear damage. Notably, the predation problem is not yet considered significant. Second, there is evidence that understory laying hen systems are profitable and have been welcomed and supported by farmers and governments in the southwest, south, and north of China. However, whether it can be scaled up is uncertain, and further research is needed. In addition, laying hens in this management system face various risks, such as foot injury, parasitism, and high dependence on consumer markets, which must be considered. Overall, agro-forestry, or accurately, understory poultry raising, provides opportunities and possibilities for free-range laying hens and welfare improvement in China and other countries.

Effect of stocking density and age on physiological performance and dynamic gut bacterial and fungal communities in Langya hens

Background

The characterization of colonization and dynamic changes related to gut microorganisms might be vital, as it presents an opportunity to quantify the co-variation between stocking densities and gut microbiome of dynamic distribution. The objective of this study was to determine the stocking density on physiological performance and dynamic distribution of gut microbiome (including bacterial and fungal communities) of Langya laying hens in the two development stages.

Methods

A randomized design with 2 × 3 factorial controls consisting of two development stages (24, 43 weeks-old) with three different stocking densities was performed. Three different stocking densities were allocated to a total of 300 11-week-old Langya laying hens (450 cm²/bird, 675 cm²/bird, 900 cm²/bird). Three housing densities were accomplished by raising different chickens per cage with the same floor size. The dependent variables of stocking densities at each sampling point were; growth performance, organs index, egg quality and the changes of dynamic gut bacterial and fungal communities in the cecum.

Results

Results showed that the stocking density didn’t affect liver index, eggshell thickness, breaking shell strength and egg shape index. Hens from the highest stocking density had the lowest body weight, fallopian tube index, egg weight and yolk colour score. Except for the yolk colour score, the measurement changes caused by age followed the opposite pattern as stocking density. We observed a substantial rise in taxa linked with health threats when stocking density was increased, including Talaromyces, Oscillospiraceae_UCG-002, Oscillospira, and Dielma. The opposite was observed with Bacteroides, Bifidobacterium, Lachnoclostridium, Eisenbergiella, and Kurtzmaniella. Also, most taxa were linked to polymicrobial infection in clinical cases, especially species whose percentage declined as the hens aged, such as Terrisporobacter, Faecalicoccus, Dialister, Cylindrocarpon etc. Whereas Sellimonas, Mitsuokella, Eurotium, Wardomyces and Cephalotheca had the opposite trend.

Conclusion

We speculated that excessive high density drove the abundance of bacteria and fungi connected with health problems. Where the gut microecology gradually reach a mature and balance status with age. Overall, this study demonstrates gut microbiome ecological processes in Langya layers at various stocking densities and finds possible connections between stocking density, microbiome and production performance. Our study will contribute to new insights associating suitable density patterns and production performance in laying hens by harnessing such a relative microbiome.

Comparison of Performance, Egg Quality, and Yolk Fatty Acid Profile in Two Turkish Genotypes (Atak-S and Atabey) in a Free-Range System

Simple Summary

In recent years, consumers have shown increased interest in healthy and safe food produced under improved animal welfare standards. Therefore, production systems proving outdoor access have gained popularity, increasing the need for knowledge on genotypes suitable for free-range systems. This study aimed to investigate the suitability of two Turkish layer genotypes, Atak-S (brown) and Atabey (white), in a free-range system. We evaluated laying performance, egg quality parameters, and yolk fatty acid profile. The egg production was higher in Atabey than Atak-S, whereas the eggs from Atak-S hens tended to be heavier and had a stronger shell structure than eggs from Atabey hens. Furthermore, eggs from Atabey hens had improved egg yolk and albumen content compared to eggs from Atak-S hens. The total saturated fatty acid content in yolk was higher in Atabey eggs than in Atak-S eggs at 56 weeks of age, whereas a higher yolk color score was observed in Atak-S eggs than in Atabey eggs. Our results could help free-range egg producers to improve production, as well as satisfy consumer demands regarding egg quality in organic production.

Abstract

Consumer interest in buying eggs from animal welfare-friendly systems with outdoor access is increasing, leading to an increase in the need for knowledge on genotypes suitable for free-range systems. Two Turkish laying hen genotypes, Atak-S (brown, n = 210) and Atabey (white, n = 210), were reared in a free-range system from 19–72 weeks of age, and their suitability for the system was assessed based on laying performance, egg quality, and yolk fatty acid profile. Mean hen-day and hen-housed egg production were found to be higher in Atabey than Atak-S (p < 0.01). The brown eggs from Atak-S hens tended to be heavier than the white eggs from Atabey hens (p < 0.01). Brown eggs obtained from Atak-S hens had a stronger shell structure (p < 0.01), while white eggs from Atabey hens had higher mean yolk index, albumen index, and Haugh unit than brown eggs (p < 0.05). At 56 weeks of age, total saturated fatty acid content in yolk was higher in white eggs than in brown eggs (p < 0.01). These findings related to genotype could help free-range egg producers in their choices for more profitable production and for meeting consumer demands on egg quality and egg yolk fatty acid levels.

Effects of poor plumage conditions on egg production, antioxidant status and gene expression in laying hens

The objective of this study was to investigate the effects of poor plumage conditions on production performance, antioxidant status and gene expression in laying hens. Two hundred ten 54-week-old laying hens with similar body weights were assigned into two groups based on plumage conditions (the poor plumage conditions (PPC) group and the control group). All the birds had free access to water and crumbled feed, and received the same management in step cages. Compared with hens in the control group, the hens in the PPC group consumed more feed and produced lighter eggs (P < 0.05). Hens in the PPC group showed lower serum concentrations of glutathione peroxidase and total antioxidant capacity and higher malondialdehyde content than those in the control group. The eggshell breaking strength was lower in the PPC group than in the control group (P < 0.05). The eggshell shape index and yolk colour in the PPC group were significantly higher than those in the control group. The mRNA expression level of HTR2C in the neck skin and that of IL-2 in the liver and breast muscle were higher in the PPC group than in the control group (P < 0.05). The results indicated that PPC may increase feed consumption and influence egg quality, antioxidant status and gene expression in laying hens.

Effect of genotype and some shell quality traits on lysozyme content and activity in the albumen of eggs from hens under the biodiversity conservation program

The aim of the study was to determine shell quality of eggs laid by some strains of native breed hens of different ages, with special consideration of their effect on lysozyme concentration and enzymatic activity. Evaluation was made of the eggshells from 6 breeds/strains of laying hens covered by the gene pool protection program in Poland: Greenleg Partridge (Z-11), Yellowleg Partridge (Ż-33), Rhode Island Red (R-11), Rhode Island White (A-33), Sussex (S-66), and Leghorn (H-22). Significant (P ≤ 0.01) differences were established for all the shell quality characteristics between hen strains. As the birds aged, shell weight and porosity increased, and shell compression strength decreased in all the experimental groups. Lysozyme content was lowest in white-shelled eggs (H-22) and highest in cream-colored and light brown eggs (Z-11, Ż-33, and R-11). Furthermore, age of hens had a greater effect on lysozyme concentration and activity in the eggs than on shell quality traits. Regardless of the layer genotype, eggs from older hens showed higher lysozyme concentration and enzymatic activity.

Effect of dietary 25-hydroxycholecalciferol supplementation and high stocking density on performance, egg quality, and tibia quality in laying hens

This study was conducted to determine the effects of 25-hydroxycholecalciferol (25-OH-D₃) on performance, egg quality, tibia quality, and serum hormones concentration in laying hens reared under high stocking density. A total of 800 45-week-old Lohmann laying hens were randomly allotted into a 2 × 2 factorial design with 2 levels of dietary 25-OH-D₃ levels (0 and 69 μg/kg) and 2 rates of stocking densities [506 (low density) and 338 (high density) cm²/hen]. Laying hens were monitored for 16 wk. High stocking density decreased laying rate, egg weight, and feed intake compared with low stocking density (P < 0.01) during 1 to 8 wk and 1 to 16 wk. Overall, high stocking density increased eggshell lightness value and decreased shell redness and yellowness value, strength, thickness, and relative weight compared with low stocking density (P < 0.05). Dietary supplementation with 25-OH-D₃ reduced the value of the eggshell lightness and increased its yellowness and eggshells weight (P ≤ 0.05). The increase in eggshell thickness was more pronounced when 25-OH-D₃ was supplemented to layers under high stocking density (interaction, P < 0.05). Layers under high stocking density had lower ash content and calcium content in the tibia than layers under low stocking density (P = 0.04); dietary 25-OH-D₃ increased tibia strength compared with no addition (P = 0.05). Layers under high stocking density had higher serum concentrations of 25-OH-D₃, corticosterone (CORT), lipopolysaccharide (LPS), and osteocalcin (OC; P < 0.05), lower content of parathyroid hormone (PTH) compared with layers under low stocking density (P < 0.01). Dietary 25-OH-D₃ increased serum concentration of 25-OH-D₃, carbonic anhydrase (CA), and calcitonin (CT) (P < 0.01) and reduced corticosterone, lipopolysaccharide and osteocalcin concentration (P ≤ 0.05). The increase effect in PTH was more pronounced when 25-OH-D₃ was supplemented to layers under high stocking density (interaction, P = 0.05). Overall, the results gathered in this study indicate that high stocking density result in reducing production performance, shell color and quality, and tibia health, whereas dietary 25-OH-D₃ was able to maintain tibia health and to mitigate the negative impact of high stocking density on productive performance.

Effects of indoor stocking density on performance, egg quality, and welfare status of a native chicken during 22 to 38 weeks

This study investigated the effects of indoor stocking density on performance, egg quality, and welfare status of a native chicken, Beijing You Chicken (BYC), during 22 to 38 wk. A total of 1,040 19-wk-old BYC pullets were randomly allocated to 4 groups (2 replicates each) and reared in 8 individual floor pens with separate covered shed and uncovered outdoor areas. The indoor stocking densities were 5, 6, 7, and 8 hens/m2, and the birds were fed corn-soybean based diets. The performance was calculated for 22 to 30, 30 to 38, and 22 to 38 wk, and egg quality indices were measured at the end of weeks 26, 29, and 36. The feather cover and gait score of the birds were assessed at the end of weeks 29 and 36. The results showed that average feed intake (AFI) and mortality rate of BYC in the 8 hens/m2 group were higher than other groups during 22 to 30 wk (P = 0.001 and P = 0.005); the egg mass and egg-laying rate were higher in groups with lower stocking density, in contrast to the feed egg ratio during 30 to 38 wk. The AFI, mortality rate, and 38-wk body weight were affected by stocking density during 22 to 38 wk (P < 0.05). Most of egg quality indices were not changed by stocking density (P > 0.05), except for individual indicators, such as Haugh unit at week 26 (P = 0.012) and egg grade at week 29 (P = 0.026). The feather cover and gait scores of birds were affected by indoor stocking density at 36 wk of age, with the 8 hens/m2 group having lower scores than the 5, 6, and 7 hens/m2 groups (P = 0.042 and P = 0.039), whereas the 7 hens/m2 groups having no difference with the 5 and 6 hens/m2 groups (P > 0.05). Overall, the results suggested that the performance and egg quality of BYC were not significantly affected by equal to or less than 7 hens/m2 under this system (P > 0.05), but 8 hens/m2 had an adverse effect on the performance and welfare status of the native chicken during 22 to 38 wk.

Performance, behavior, and health of male broilers and laying hens of 2 dual-purpose chicken genotypes

Dual-purpose chicken where both sexes are reared together, before males are separated for final fattening, while females are kept for an entire laying period, may provide an economic alternative under certain production and marketing conditions. Two genotypes, purebred Bresse-Gauloise (PURE, n = 300) and crossbred Bresse-Gauloise × New Hampshire (CROSS, n = 300), were compared. One-day-old mixed-sex chicken were raised for 12 wk under floor husbandry conditions on a broiler diet. Thereafter, males were transferred to a mobile chicken house with free-range access. Males were slaughtered at weekly intervals from 12th to 19th wk of age. Hens were kept for 1 laying period in a mobile house. Growth performance, feed consumption, carcass, meat quality, health and welfare traits were measured in both sexes. In females layers’ performance, egg quality and behavior were recorded, too. At 12 wk, males of PURE reached a live weight of 2,075 g and CROSS of 1,865 g (P < 0.05), while at 16 wk both weighed more than 2,500 g (P > 0.05). Dressing percentage increased with slaughter age and was above 68% in both genotypes when slaughtered at 18 to 19 wk of age. Proportion of legs, breast, and wings was 34.3, 16.0, and 11.0% in PURE and 34.7, 15.5, and 12.1% in CROSS (P > 0.05). Laying performance was 54.5% in PURE and 54.2% in CROSS (P > 0.05). Egg breaking strength decreased during the laying period, but remained above 30 N. Feed conversion was 3.4 kg feed/kg egg. On average, 25% of the animals stayed outdoors during daytime (P > 0.05). Keel bone deformations were observed in 10% and breast blisters in 20% of the hens. Under the specific conditions of marketing products with added value, performances resulted in an overall economic benefit, which was higher for PURE than CROSS. The use of dual-purpose chicken to avoid the killing of 1-d-old chicken and mobile housing may substantiate premium prices in such a system.