Macroscopic and histopathological alterations of foot pads of laying hens kept in small group housing systems and furnished cages

1. Foot pad health was determined macroscopically and histologically in two trials with Lohmann Selected Leghorn (LSL, white layer strain) and Lohmann Brown (LB) laying hens kept in a small group housing system (40 and 60 hens) and two types of furnished cages (10 and 20 hens). 2. A total of 864 foot pads (648 LSL and 216 LB) were examined macroscopically and classified according to severity of pathological alterations; of these, 180 metatarsal pads and 180 toe pads were also examined histologically for hyperkeratosis, acanthosis, elongation of rete folds, development of secondary papillae, erosion, ulceration, cellular infiltration and bacterial colonisation of the epidermal surface. 3. As for the macroscopic examinations, pathological alterations of foot pads were found in 86.1% of the hens, while 57.4% of the birds examined showed mild hyperkeratosis. Macroscopically moderate hyperkeratosis and/or superficial lesions of the epithelium were detected in 21% of the laying hens examined. Severe hyperkeratosis and/or deep epithelial lesions and/or mild swelling of the foot pads were found in 5.9% of the hens, and very severe hyperkeratosis and/or deep and large epithelial lesions and/or moderate or high-grade swelling of foot pads were found in 1.9%. 4. The histopathological examinations showed that the macroscopically determined thickening of the epidermis was due not only to hyperkeratosis, but also often to acanthosis. In addition, perivascular infiltrations of lymphocytes were also detected. Furthermore, the degree of hyperkeratosis in metatarsal pads was shown to correlate with the other histopathological traits except for ulceration, and the degree of hyperkeratosis in toe pads was related to the development of secondary papillae and cellular infiltration with lymphocytes. 5. The results of the macroscopic and histological examinations showed that the use of perches and the grasping of wire floor may have resulted in a permanent increased mechanical compression load leading to proliferative hyperkeratosis.     

Effect of furnished small group housing systems and furnished cages on mortality and causes of death in two layer strains

1. Mortality and causes of death were recorded over two trials with 13045 Lohmann Selected Leghorn (LSL, white layer strain) and 4410 Lohmann Brown (LB) laying hens kept in furnished small group housing systems and furnished cages. In trial 1, hens were housed from weeks 19 to 71 (LSL) and 17 to 69 (LB). In trial 2, LSL hens were housed from weeks 18 to 57. 2. The hens were kept in groups of 40 and 60 in the furnished small group housing system Eurovent 625 + a-EU and in groups of 10 and 20 in the furnished cages Aviplus and Eurovent 625A-EU. 3. To investigate the possible effect on mortality of rearing the birds on litter floors or in cages, in trial 2 half of the LSL hens were reared on the floor and half in conventional cages. 4. Mortality was greater in the Eurovent furnished small group housing system (5.2%) than in the furnished cages Aviplus (4.0%) and Eurovent (4.2%). 5. Mortality was also affected by the interactions among housing system and trial, layer strain and rearing. In trial 1, more LB laying hens died in the Aviplus system than in the Eurovent group system. There was no significant difference in mortality of the LSL laying hens between housing systems in trial 1. In trial 2, mortality of the LSL hens was greater in the group housing system (hens reared on litter floors: 10.1%; hens reared in cages: 2.8%) than in the furnished cage Aviplus (hens reared on litter floors: 6.0%; hens reared in cages: 1.5%). 6. Mortality was greater in floor-reared LSL laying hens than in the LSL laying hens reared in conventional cages. 7. Group size within housing system had no significant effect on mortality. 8. The most common findings at autopsy were different types of cannibalism (65.51%), with vent cannibalism (38.57%) the most common.     

Occurrence of organic diseases and parasitoses in layer strains Lohmann Selected Leghorn and Lohmann Brown kept in small group housing systems and furnished cages during the laying period

The state of health was examined over two laying periods in a total of 648 Lohmann Selected Leghorn (LSL) and 216 Lohmann Brown (LB) laying hens kept in small group housing systems and furnished cages. In addition, the effect of group size, month of laying, trial, rearing method and body weight was tested. Autopsies of clinically healthy hens were performed every three months during the laying period. Diagnosed fatty livers were classified in three severity codes ranging from moderate to severe alteration. Continuative liver diagnostic was performed by analysing triacylglycerol concentration in serum of every hen. The most common diagnoses at autopsy of clinically healthy laying hens were fatty livers (53.9% in the first trial and 46.3% in the second) and diseases of the reproductive organs. In both trials, there was a significant effect of month of laying and body weight on the occurrence of fatty liver. In the second trial, the occurrence of fatty liver was also significantly affected by the housing system: fatty livers were found significantly most frequently in the Eurovent 625A-EU system. The effect of group size within housing system, layer strain and rearing method regarding the individual trials were found to be not significant.The serodiagnosis showed that laying hens with macroscopically assessed fatty livers had significantly greater triacylglycerol concentrations in serum than the laying hens without fatty livers. Endoparasites did not mean a health problem. In contrast, the red mite of poultry was detected in each examined system.     

Aviary Systems and Conventional Cages for Laying Hens: Effects on Production,Egg Quality,Health and Bird Location in Three Hybrids

Abstract

In two experiments, a total of 4346 laying hens housed in battery cages, with three hens per cage (C), and in two aviary systems, both with tiered wire floors and litter (Lövsta with two tiers (L) and Marielund with three tiers (M)), were used for studies on production, egg quality, health, plumage and foot condition, bone strength and bird location. Three hybrids were used: Lohmann Selected Leghorn (LSL) were kept in all three systems, Dekalb XL (DK) were kept in both aviaries and Lohmann Brown (LB) in M only. Production and feed conversion in M were inferior but not significantly different from C but significantly better than in L. Proportions of dirty eggs were significantly higher in the avaries. No significant differences were found in interior egg quality traits between keeping systems. LSL showed higher production and better feed conversion than the other hybrids and a tendency for a lower proportion of mislaid eggs. Mortality varied considerably between the aviary pens, reaching 35% in LB mainly owing to cannibalism and salpingitis. Keel bone lesions and bumble foot appeared in the aviaries, while toe pad hyperkeratosis was observed in C. Hens in aviaries had significantly stronger bones (tibia and humerus) and showed more wounds from pecks, inferior plumage condition and dirtier feet than in C. LSL had more bumble foot injuries than LB but better plumage condition than DK. The birds used the different parts in the aviaries well, especially the perches on the resting top tier during the night.     

Genetic resistance to natural helminth infections in two chicken layer lines

Groups of Lohmann Brown (LB) and Lohmann Selected Leghorn (LSL) hens were reared under helminth-free conditions and kept afterwards together in a free range system. Mortality rate, body weight development, laying performance and faecal egg counts (FEC) were recorded during a 12 month laying period. At the end of the laying period, 246 LSL and 197 LB hens were necropsied and worms counted following the World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.) guidelines. In addition adult Heterakis gallinarum and Ascaridia galli were sexed and measured for length. Significant (P<0.01) differences were observed in mortality rates between LSL and LB animals (12.9 vs. 5.7%). LSL hens showed significantly (P<0.05) higher FEC when compared with LB hens at almost all dates of monitoring. Almost all animals became infected with at least one helminth species. The most prevalent species were H. gallinarum, Capillaria spp. and A. galli. LB hens showed a significantly (P<0.05) higher average number of adult H. gallinarum, Capillaria spp. and tapeworms when compared with LSL animals. However, number of adult A. galli was in tendency lower in these animals. In total, LB had a significantly (P<0.05) higher worm burden than LSL (192.3 vs. 94.3). The estimated heritabilities for total worm burden were 0.23 (SE±0.12) in LSL and 0.75 (SE±0.21) in LB, respectively. The number of all different helminth species were positively correlated. The sex ratio of H. gallinarum and A. galli and the average worm lengths were not significantly (P>0.05) different between the genotypes. There was no significant phenotypic correlation between body weight and worm burden in LSL, whereas it was the case in LB (r=0.17, P<0.05). Based on the estimated heritabilities it is possible to select for helminth resistance in both genotypes.     

Welfare of layers housed in small furnished cages on Danish commercial farms: the condition of keel bone,feet, plumage and skin

1. An on-farm assessment of keel bone, feet, plumage and skin damage was conducted in layers in small furnished cages to evaluate welfare implications.

2. Thirteen farms participated, all housing Lohmann LSL layers in systems allowing 8 or 10 hens per cage.

3. Each flock was visited at three different ages: 32, 62 and 77 weeks. During each visit, 100 hens were examined for keel bone fractures and deviations, plumage damage, body wounds, foot pad lesions, bumble feet, missing toes and toe wounds.

4. A deterioration with age of the condition of the plumage and keel bone was found (P < 0.001). At 77 weeks of age, 16% of the birds had poor plumage, and 43% of the birds had keel bone damage. In contrast, foot pad lesions were most prevalent at 32 weeks of age (13%), whereas the other foot injuries and body wounds remained at a relatively low level throughout the three ages examined.

5. Prevention of damage to the keel bone, plumage and foot pads should therefore be considered when aiming to improve welfare of laying hens housed in small furnished cages.     

Effects of dietary protein on egg production of laying hens housed in furnished or conventional cages

Abstract

In the present experiment the effects of dietary protein content on egg production of hens kept either in conventional cages (CCs) or furnished cages (FCs) were studied. A total of 1088 LSL (Lohmann LSL-Classic Layer) hens were housed in either FCs or CCs and offered high or low protein diets with a protein/energy ratio of 17 or 13, respectively, during three consecutive feeding phases of 20, 16 and 16 weeks, respectively. There was no interaction between the effects of cage design and of dietary treatment on laying performance. Hens kept in FCs consumed less feed than hens in CCs (p<0.05). After the first feeding phase, hens housed in FCs produced fewer eggs (p<0.01) than hens in CCs. No differences in the feed conversion ratio were found between the housing systems. Hens on the low protein diet laid smaller eggs than hens on the high protein diet (p<0.001). No effect of dietary protein on laying rate was found. It can be concluded that dietary protein affects egg production irrespective of the cage type.     

Effects of a high oil and fibre diet and supplementary roughage on performance, injurious pecking and foraging activities in two layer hybrids

1. The study investigated the feeding of a high oil and fibre diet containing 260 g/kg organically produced cold pressed sunflower cake or supplemental roughage to aviary-housed Lohmann Selected Leghorn (LSL) and Lohmann Brown (LB) layers between 20 and 74 weeks of age with outdoor access during summer. 2. Feeding roughage was associated with reduced vent injuries, a tendency to improve plumage condition, and was accompanied by improved FCR compared with controls. Feeding the high oil and fibre diet tended to improve FCR compared with the control diet. 3. The dry matter of faeces was reduced in both treatments compared with controls. Foot pad cleanliness and the proportion of dirty eggs were negatively affected by the high oil and fibre diet. Foot health was superior in LB compared to LSL. 4. LB used the outdoor hen-runs more than LSL, but LSL consumed more litter indoors. Fewer LB hens fed on the control feed were recorded in the outdoor hen-runs. Supplemental roughage tended to decrease litter consumption. 5. In conclusion, supplemental roughage reduced vent injuries and was correlated with foraging activities. Feeding 260 g/kg sunflower cake negatively affected hygiene in aviary hens. Sunflower cake is nevertheless a promising alternative feedstuff to fulfil the protein requirement in organic layers.     

Influence of Ascaridia galli infections and anthelmintic treatments on the behaviour and social ranks of laying hens (Gallus gallus domesticus)

In the present study, the effects of an experimental Ascaridia galli infection and anthelmintic treatment on the behaviour and social status of laying hens of two different lines were studied. Sixty white (Lohmann LSL; LSL) and 60 brown (Lohmann Brown; LB) hens were reared under helminth-free conditions. The hens of each line were divided into four groups. The birds in two of the groups were artificially infected with 250 embryonated A. galli eggs at an age of 27 weeks. The other two groups were kept as uninfected controls. One infection and control group was dewormed at 38 weeks of age and slaughtered 4 weeks later, contemporary with the other animals. Individual faecal Ascaridia egg counts (FEC) were performed 11 weeks post-infection (p.i.). Body weights, laying performance and egg weights were recorded regularly. Blood was taken to measure testosterone levels. The worm burdens established in the intestines were counted in the infected not treated group after slaughtering. In addition, 15 behavioural parameters were recorded by focal animal observation (n=10 per group) of one infection (plus anthelmintic treatment) and one control group, according to the time-sampling method throughout the experiment. All agonistic interactions within the groups were recorded simultaneously on an ongoing basis, thereby allowing the calculation of an individual social rank index. The following results were obtained: Mean FEC and worm burden were higher (p < 0.01) in the LSL hens than in the LB hens, but their performances were not different (p > 0.05) from the controls. Infections with A. galli resulted in significant behavioural changes in both lines as the infected birds showed a higher food intake and lower locomotion activity during the prepatent and patent periods. After anthelmintic treatment, food intake decreased and locomotion increased. Behavioural changes were more pervasive in the infected LSL hens, as these hens also showed changes in ground pecking and nesting activity not only during the prepatent and patent periods, but also after anthelmintic treatment. Social rank did not significantly change as a consequence of A. galli infection, but the infection groups of both lines had a tendency to display more agonistic activity than the non-infected controls. Serum testosterone values only increased significantly in the LSL hens during the patent period compared to the controls. No significant correlations were apparent between serum testosterone level, parasitic parameters, social status and/or aggressiveness in any of the groups. This study showed that even sub-clinical A. galli infections and their anthelmintic treatment can have an impact on animal behaviour.     

Keeping laying hens in furnished cages and an aviary housing system enhances their bone stability

1. Tibia and humerus breaking strength of Lohmann Silver hybrids kept in conventional cages, furnished cages and an aviary with outdoor run were examined in two production cycles. Each trial lasted a full laying period; feeding, management and healthcare were identical for all hens. In both trials bone strength was investigated at the end of laying months 6, 9 and 14. 2. The objective was to determine if bone strength increases when hens are kept in alternative housing systems, especially in furnished cages, and whether hen age affects bone stability. 3. The results indicated that housing system influenced bone breaking strength, which was consistently higher for hens in the aviary compared to hens in conventional and furnished cages. Furthermore, humerus breaking strength was higher for hens in furnished cages compared to conventional cages. No significant difference regarding tibia breaking strength was found between conventional and furnished cages. 4. Our results showed that lack of exercise contributed to the problem of weak bones more than did calcium depletion from eggshell formation. 5. Tibia breaking strength increased during the last third of the production cycle, whereas humerus breaking strength remained unaffected by hen age. 6. Genetic group affected only tibial bone breaking strength, which was lower overall in genetic group A than in group B, which in turn was lower than group C. 7. The increased bone strength in the aviary and in the furnished cages probably reduced the incidence of recently broken bones in these systems compared to the conventional cages. This increase in bone strength can be regarded as an improvement in welfare. Furnished cages, like the aviary system, might be considered an alternative housing system for laying hens, because both resulted in enhanced bone strength.     

Fat status in Lohmann Silver and Lohmann tradition laying hens kept in modified small group housing systems, small group housing systems, furnished cages and an aviary system

The influence of different housing systems on adiposis of liver, abdomen and heart was evaluated in 670 Lohmann Silver (LS) and 240 Lohmann Tradition (LT) laying hens during two trials. Examinations took place in the 3rd, 6th, 9th and 12th laying month. In addition, serum concentration of triglycerides (TRI) was analysed. Housing systems included in this study were a furnished cage system (Aviplus (AP)), a small group housing system (Eurovent 625a-EU (EV)), with perches on the same (first trial) and on different levels (second trial, MEV), and an aviary system (Voliere Natura (AV)). In both trials, a significantly lower fat status of abdomen and liver could be observed in hens housed in AV. Consistently in both trials, body weight and housing system had the largest influence on fat status of liver, abdomen and heart. Scores of fat status of liver and abdomen in EV and MEV were in between of those observed in AV and AP, while heart fat status did not differ among housing systems. With an increasing macroscopic fat status of the liver, liver weight and TRI concentration significantly increased. Different perch positions in MEV did not have a significant influence on fat status in layers.     

Progression of histomonosis in commercial chickens following experimental infection with an in vitro propagated clonal culture of Histomonas meleagridis

Four commercial strains of chickens, namely, ISA brown leghorn (ISA), TETRA-SL brown (TETRA-SL), Lohmann brown (LB), and Lohmann LSL (LSL), were infected with a well-defined clonal culture of Histomonas meleagridis (H. meleagridis/Turkey/Austria/2922-C6/04) to investigate their susceptibility to histomonosis. Each group included 16 chickens, which were housed under the same conditions in separate pens. All chickens were infected with 10(4) histomonads orally and intracloacally at 14 days of age. No mortality or clinical signs were observed during the experiment in all birds. Three birds of each chicken strain were euthanatized on days 4, 7, 10, 14, and 21 postinfection. Incidence of histomonosis on the basis of cecal lesions was found to be 64.00% in TETRA-SL, 62.50% in LB, 53.12% in LSL, and 43.75% in ISA chickens. Fewer lesions were noticed in livers than in ceca, with an incidence of 15.62% in TETRA-SL, 9.37% in LB, and 3.12% in ISA chickens. No liver lesions were found in the LSL chickens. Statistical analysis revealed that there was no significant difference (P > 0.05) in susceptibility to experimental H. meleagridis infection based on cecal and liver involvement. Polymerase chain reaction (PCR) and immunohistochemistry were found to be reliable tools to confirm the presence of histomonads and changes in the ceca. However, some negative PCR results were recorded from the livers despite the presence of macroscopic lesions. Additionally, DNA of H. meleagridis was detected by PCR in a few of the lungs, but immunohistochemistry was negative. Nucleic acid of the protozoan parasite was not detected in samples from kidney, brain, spleen, or bursa of Fabricius. Altogether, the high susceptibility of commercial chicken lines to histomonosis could be demonstrated and characterized by severe lesions in the ceca and insignificant involvement of the liver, approaching a maximum on days 7-14 postinfection.     

Exogenous estradiol improves shell strength in laying hens at the end of the laying period

Background

Cracked shells, due to age related reduction of shell quality, are a costly problem for the industry. Parallel to reduced shell quality the skeleton becomes brittle resulting in bone fractures. Calcium, a main prerequisite for both eggshell and bone, is regulated by estrogen in a complex manner. The effects of estrogen, given in a low continuous dose, were studied regarding factors involved in age related changes in shell quality and bone strength of laying hens. A pellet containing 0.385 mg estradiol 3-benzoate (21-day-release) or placebo was inserted subcutaneously in 20 birds each of Lohmann Selected Leghorn (LSL) and Lohmann Brown (LB) at 70 weeks of age. Eggs were collected before and during the experiment for shell quality measurements. Blood samples for analysis of total calcium were taken three days after the insertion and at sacrifice (72 weeks). Right femur was used for bone strength measurements and tissue samples from duodenum and shell gland were processed for morphology, immunohistochemical localization of estrogen receptors (ERα, ERβ), plasma membrane calcium ATPase (PMCA) and histochemical localization of carbonic anhydrase (CA).

Results

Estrogen treatment increased shell thickness of both hybrids. In addition, shell weight and shell deformation improved in eggs from the brown hybrids. The more pronounced effect on eggs from the brown hybrid may be due to a change in sensitivity to estrogen, especially in surface epithelial cells of the shell gland, shown as an altered ratio between ERα and ERβ. A regulatory effect of estrogen on CA activity, but not PMCA, was seen in both duodenum and shell gland, and a possible connection to shell quality is discussed. Bone strength was unaffected by treatment, but femur was stronger in LSL birds suggesting that the hybrids differ in calcium allocation between shell and bone at the end of the laying period. Plasma calcium concentrations and egg production were unaffected.

Conclusions

A low continuous dose of estrogen improves shell strength but not bone strength in laying hens at the end of the laying period.     

Effect of housing environment on laying hen meat quality: Assessing Pectoralis major pH,colour and tenderness in three strains of 80–81 week-old layers housed in conventional and furnished cages

1. Meat quality is affected by factors such as stress, genetic strain and activity and is determined in part by measures of pH, colour and tenderness. In conventional laying hen cages (CC), lack of physical space and inability to perform highly motivated behaviours leads to stress and inactivity. Furnished cages (FCs) permit expression of highly motivated behaviours, but typically house larger group sizes than CC, thereby contributing to social stress. The objective of this study was to evaluate the effects of CC and FC laying hen housing environments and strain differences on meat quality of 80–81-week-old birds.

2. Pectoralis major meat quality was assessed for two flocks of Shaver White (SH), Lohmann Lite (LL) and Lohmann Brown (LB) hens housed in either 5-hen CC or 40-hen FC. Between 80 and 81 weeks, muscle samples were collected from randomly selected hens and analysed for muscle pH, colour and shear force (SF) using established methods.

3. In both flocks, the combined treatment body weights (BWs) were higher for CC than FC hens and the combined strain BWs were higher for LB than LL and SH hens. Flock 1 LB had lower initial and ultimate pH than SH and LL, and greater pH decline than SH. Muscle redness (a*) was higher for CC SH than FC SH in both flocks. Muscle a* was higher for LL than SH and LB in Flock 1, and higher than SH in Flock 2. Housing differences in muscle SF were absent. In CC, SF was higher for SH than LL and LB in Flock 1, and higher than LB in Flock 2.

4. Lack of housing differences suggests that environmental stressors present in both housing systems similarly affected meat quality. Strain differences for muscle pH, a* and SF indicate increased stress experienced by SH and LL hens. The absence of Flock 2 strain differences is consistent with the cannibalism outbreak that occurred in this flock and most severely impacted LB hens.     

Genetic differences of Ascaridia galli egg output in laying hens following a single dose infection.

Groups of 20-week-old white (Lohmann LSL) and brown (Lohmann Brown) hens were reared under helminth-free conditions and both divided into two subgroups. One subgroup was artificially infected with 250 embryonated Ascaridia galli eggs, the other subgroup were kept as uninfected controls. During the following 12-month laying period individual faecal Ascaridia egg counts (FEC) were performed and bodyweight measured at monthly intervals. Laying performance and egg weights were determined daily. The mean FEC were significantly (P < 0.01) higher in infected white hens than in infected brown hens. The growth rate of the white hens was significantly (P < 0.05) higher in the control group, whereas in brown hens no significant group difference was observed. The laying performances and egg weights did not differ significantly (P > 0.05) between control and infected animals for either line. The estimated repeatabilities for mean log(10) FEC of different samples were reasonably high (0.16-0.54). Heritabilities for mean log(10) FEC were between 0.13 and 0.19 for white hens and between 0.0 and 0.10 for brown hens. Thus, it should be possible to select for A. galli resistance in chickens, which will be of importance for birds kept in alternative and organic farming systems.     

Behaviour,health and integument of four hybrids of laying hens in modified and conventional cages

1. In 2 trials the health and behaviour of a total of 3552 caged laying hens of 4 hybrids, Dekalb XL, Lohmann Selected Leghorn (LSL) and Shaver 288 in trial 1 and ISA Brown and LSL in trial 2, were studied. The cage designs were Get‐away cages (GA) with 15 hens per cage, a special version of the ‘Edinburgh modified cage’ called ‘Modified and enriched cage’ (ME) with 4 ISA or 5 Leghorn hens per cage, conventional metal cages with 4 hens per cage without (CO) and with a perch (PC) and conventional plastic cages (PL) with three hens per cage. GA and ME included nests, perches and sandbaths.

2. In the first trial two nest models were used, artificial turf and welded wire floor. In the second trial both nest models were used in GA, while all nests in ME were equipped with artificial turf. In the second trial there were 4 sandbath treatments in ME; no sandbath, sandbath (25×50 cm) first opened at 16 weeks of age, sandbath first opened at 26 weeks and double size sandbath (50 × 50 cm) first opened at 16 weeks. Hens in GA were allowed access to the sandbaths from 26 weeks.

3. At 35 and 55 weeks the best plumage condition (feather cover) was found in PL and GA but plumage condition in ME was not significantly inferior than in GA. Hens in GA had the dirtiest plumage and most bumble foot but no toe pad hyperkeratosis. Some toe pad hyperkeratosis occurred in the other systems. Most keel bone lesions were found in systems with perches. The highest mortality was registered in GA. Hens in systems with perches, sandbaths and nests had increased strength of humerus at slaughter.

4. More eggs were laid in nests with artificial turf than in welded wire floor nests. LSL hens laid larger proportions of eggs in the nests (94% and 92% in the two trials) than the other hybrids. Less than 1% of the eggs in ME and 2% in GA were laid in the sandbaths.

5. The use of perches in ME and PC was approximately 30% in the day time. At night the use was 93% in ME and 89% in PC in trial 1 and 96% in ME and 81% in PC in trial 2.

6. Hens in ME with the double sized sandbath both visited the sandbath and performed dust bathing behaviour most, followed by hens in GA, hens in ME with access to the bath from 16 weeks and last, hens in ME with access to the bath from 26 weeks.

7. It is concluded that enrichments of laying cages are used by the hens to a large     

Performance of Four Hybrids of Laying Hens in Modified and Conventional Cages

Abstract

In two trials, production, feed consumption, mortality, egg quality and birds' live weight of a total of 2877 caged laying hens of four hybrids, Dekalb XL, Lohmann Selected Leghorn (LSL) and Shaver 288 in Trial 1 and ISA Brown and LSL in Trial 2, were studied during full production cycles. The cage designs were Get-away cages (GA) with 15 hens per cage, a special version of the “Edinburgh modified cage” called “Modified and enriched cage” (ME) with 4 ISA or 5 Leghorn hens per cage, conventional cages of metal (CO) with 4 hens per cage and conventional cages of plastic (PL) with 3 hens per cage. GA and ME included nests, perches and sandbaths. LSL produced significantly better than the other hybrids. Shaver had a significantly lower live weight than Dekalb and LSL, while ISA was significantly heavier than LSL. Production in ME was similar to that in conventional cages and, in Trial 2, birds in ME, CO and PL produced significantly better than those in GA. The highest mortality was registered in GA, where in Trial 2 it was significantly higher than in ME. GA gave a significantly higher and CO a lower proportion of cracked eggs than ME and PL. In both trials ME gave significantly lower proportions of dirty eggs than GA and in Trial 2, the lowest. Few differences between the systems were registered regarding interior egg quality. It was concluded that ME is better for production, mortality and management than GA but similar to conventional cages.     

洪江雪峰乌骨鸡和罗曼粉蛋鸡鸡蛋营养成分和蛋品质比较

试验旨在比较洪江雪峰乌骨鸡和罗曼粉蛋鸡的鸡蛋营养成分和蛋品质,为洪江雪峰乌骨鸡蛋用新品系选育提供依据。随机选取40周龄的洪江雪峰乌骨鸡(绿壳)、洪江雪峰乌骨鸡(粉壳)和罗曼粉壳蛋鸡各100只,每品种鸡随机分为5个重复,每个重复20只,在相同饲粮和饲养管理方式下进行饲养,45周龄收集鸡蛋检测营养成分和蛋品质指标。结果表明:洪江雪峰乌骨鸡绿壳蛋的蛋黄比例极显著高于罗曼粉壳蛋(P<0.01),蛋重、蛋壳厚度、哈氏单位极显著低于罗曼粉壳蛋(P<0.01),洪江雪峰乌骨鸡粉壳蛋的蛋重和蛋壳厚度极显著低于罗曼粉壳蛋(P<0.01);洪江雪峰乌骨鸡蛋中的多不饱和脂肪酸和硒元素含量均极显著高于罗曼粉壳蛋(P<0.01),洪江雪峰乌骨鸡绿壳蛋胶原蛋白含量极显著高于罗曼粉壳蛋(P<0.01)。综上所述,洪江雪峰乌骨鸡鸡蛋蛋黄比例高,蛋黄多不饱和脂肪酸、胶原蛋白、硒和锰含量高,适合作为优质禽蛋开发。     

Outdoor use, tonic immobility, heterophil/lymphocyte ratio and feather condition in free-range laying hens of different genotype

1. Movement (frequency of changes) between inside and outside housing areas, time spent in each area, tonic immobility (TI) and differential blood cell counts were studied in relation to feather condition in laying hens of two genotypes, white (LSL) and brown (LT). 2. From 18 weeks of age, LSL and LT were kept in 4 groups of 50 birds in a poultry house with passages to a roofed scratching room and a grassland area with a stocking density of one bird/10 m2. 3. All birds had transponders to record the movements of each hen between inside and outside areas and the time spent in each area during 24 h. Feather scoring was carried out at 6 ages from 20 to 48 weeks. At 44 weeks of age, TI reactions of 40 hens (20 from each genotype) were quantified and blood smears from 20 hens (10 from each genotype) were analysed for differential leucocyte counts. 4. LSL hens moved more frequently to outdoor areas than LT hens (44.66 vs 28.78 least square/d). However, the proportion of time spent on grassland was greater in LT than in LSL hens, whereas time (%) spent by LT hens in the roofed scratching area was less than for LSI hens. 5. In LT hens TI was shorter while heterophil/lymphocyte ratio and basophilia were greater than in LSL hens. 6. Total body feather score was poorer in LSL than in LT hens. Incidence of footpad inflammation was higher in LSL than LT hens. 7. There was a positive association between TI and footpad inflammation. The percentage of time spent on grassland and feather damage were inversely correlated. 8. More movement between the areas, as in LSL hens, was positively associated with fearfulness, whereas long periods on grassland, as in LT hens, were associated with indicators of increased stress. The negative correlation between feather damage and time spent outside suggests that feather pecking risk decreases in birds attracted to grassland.     

Evaluation of bone strength,keel bone status,plumage condition and egg quality of two layer lines kept in small group housing systems

1. The aim of the present study was to determine the influence of large (54 or 60) and small (36 or 40) group sizes and tiers of the small group housing system “Eurovent German” on tibia and humerus bone breaking strength, keel bone status, plumage condition and egg quality for two commercial layer lines, Lohmann Selected Leghorn (LSL) and Lohmann Brown (LB), at the same stocking density (890 or 830 cm²/bird).

2. In 4 consecutive trials, 4752 hens were recorded for keel bone status. Evaluation of plumage condition was made for 1440 hens and bone breaking strength was recorded for 1200 hens. A total of 4962 eggs were analysed for internal and external egg quality traits. Analyses involved 30 small group compartments per trial.

3. The layer line had a much more pronounced influence on humerus breaking strength than on tibia breaking strength.

4. Plumage condition, particularly on the neck, was positively correlated with humerus breaking strength in both layer lines.

5. An average of 34% of LB and 23% of LSL hens showed keel bone deformities, with higher proportions of slight deformities.

6. Slight keel bone deformities, rather than moderate to severe, increased significantly during the laying period.

7. Stocking density had no influence on bone breaking strength, keel bone status and egg quality traits.

8. LB layers had a 1.4-fold higher humerus, but only a 1.06-fold higher tibia breaking strength compared to LSL layers.

9. Tibia breaking strength was significantly affected by the interaction of group size and layer line. LSL layers in small groups had lower tibia breaking strengths than those of the large groups.