Effects of Furnished Cage Type on Behavior and Welfare of Laying Hens

The Gordon Memorial Lecture: Laying Hen Welfare

Preference tests remain a useful tool in the assessment of laying hen welfare and have been used to establish what types of resources and enrichments are most likely to meet the birds' needs. Evidence on the underlying structure of bird preference suggests that hens make stable and reliable choices across time and context. This means that their preferences can also be used as a benchmark in the validation of other welfare indicators. Hens have sophisticated cognitive abilities. They are quick to form associations between events and they are flexible in how they apply their knowledge in different contexts. However, they may not form expectations about the world in the same way as some mammalian species. Limited research in this area to date seems to show that hens judge situations in absolute terms rather than evaluating how a situation may be improving or deteriorating. The proportion of hens housed in cage-free systems is increasing globally, providing birds with greater behavioural freedom. Many of the problems associated with cage-free systems, such as keel bone fractures, mortality and injurious pecking, are slowly reducing due to improved experience and appropriate changes in rearing practices, diet, housing design and alignment of breeding goals. However, much remains to be done. The design and performance of veranda-based systems which provide hens with fresh air and natural light is a promising avenue for future research aimed at optimising hen welfare and improving sustainability.

Health in poultry- immunity and microbiome with regard to a concept of one health

The overall concept of OneHealth focuses on health and infectious disease in the context of the relationship between humans, animals, and the environment. In poultry production, there are many opportunities to implement OneHealth by organizing work and introducing appropriate engineering solutions. It is recommended that future research directions include designing and testing solutions to improve air quality and the elimination of antibiotics in the poultry industry. For this to be possible, it is essential to understand the indigenous microbiota of poultry, which plays a crucial role in nutrients, but also restricts the growth of pathogenic organisms. In poultry production, the most important thing is disease control in the herd, high product quality, and product efficiency. Food safety is key for consumers, as some zoonoses are transmitted through the food chain. Moreover, antibiotic resistance of bacteria is becoming a growing threat. For this reason, it is essential to maintain the proper immune status in the herd. Virus disease control in poultry is based on vaccination programs and the maintenance of biosecurity. This chapter aims to present the current state of knowledge in the field of immunity and microbiome of poultry in the context of the OneHealth concept.

Dietary supplementation with β-mannanase and probiotics as a strategy to improve laying hen's welfare

A trend toward animal welfare improvement is observed in animal production, in addition to restrictions imposed on the use of antimicrobials. This study's objective was to evaluate whether β-mannanase and probiotic supplementation can change hen's behavior. Light weight laying hens (36 weeks old) were housed in cages randomly allocated to one of four different treatments: control group, fed non-supplemented diets; diets supplemented with 300 g/ton of β-mannanase; diets supplemented with 50 g/ton of probiotic; or diets containing both 300 g/ton of β-mannanase and 50 g/ton of probiotic. The behavior of 24 birds was recorded for a week using video cameras. The frequency and time of main behaviors (eating, walking, standing, sitting, drinking, and exploring) were analyzed in three periods per day (from 09:00 to 09:15; from 01:00 to 01:15, and from 04:00 to 04:15), as well as the time of other behaviors (leg-stretching and wings, scratching, wing-flapping, aggressive and non-aggressive pecks). Frequency and lesion scores were also analyzed using a visual score of three body regions: neck, tail, and cloaca; as well as comb injuries. β-mannanase was able to increase the frequency of feeding behavior by 49% (P < 0.05) and hens also spend 20% (P < 0.05) more time in this behavior compared to the control treatment. The use of probiotics also enhanced by 39% (P < 0.05) the frequency and 19% the time (P < 0.05) and the supplementation with combined additives was able to increase by 29% (P < 0.05) the frequency and 25% (P < 0.05) the time in feeding behavior. β-mannanase and probiotics also increased the frequency and time spent exploring behavior (P < 0.05) and promoted a higher frequency in standing behavior (P < 0.05) and decreased the time spent on sitting behaviors (P < 0.05). The combined additives showed less frequency and time in sitting behaviors (P < 0.05), while increased wing-flapping behavior (P < 0.05). All the treatments were able to reduce pecking (P < 0.05). Therefore, the addition of β-mannanase and probiotics to laying hen diets is an effective strategy to improve bird welfare.

Effects of Housing System on Anxiety, Chronic Stress, Fear, and Immune Function in Bovan Brown Laying Hens

The scientific community needs objective measures to appropriately assess animal welfare. The study objective was to assess the impact of housing system on novel physiological and behavioral measurements of animal welfare for laying hens, including secretory and plasma Immunoglobulin (IgA; immune function), feather corticosterone (chronic stress), and attention bias testing (ABT; anxiety), in addition to the well-validated tonic immobility test (TI; fearfulness). To test this, 184 Bovan brown hens were housed in 28 conventional cages (3 birds/cage) and 4 enriched pens (25 birds/pen). Feces, blood, and feathers were collected 4 times between week 22 and 43 to quantify secretory and plasma IgA and feather corticosterone concentrations. TI tests and ABT were performed once. Hens that were from cages tended to show longer TI, had increased feather corticosterone, and decreased secretory IgA at 22 weeks of age. The caged hens fed quicker, and more hens fed during the ABT compared to the penned hens. Hens that were in conventional cages showed somewhat poorer welfare outcomes than the hens in enriched pens, as indicated by increased chronic stress, decreased immune function at 22 weeks of age but no other ages, somewhat increased fear, but reduced anxiety. Overall, these novel markers show some appropriate contrast between housing treatments and may be useful in an animal welfare assessment context for laying hens. More research is needed to confirm these findings.

Effects of the genotype, cage type and time period on the behaviour of laying hybrids at the same egg production level

Hybrids with different morphological and yield characteristics are used in the table egg production. There is no change in the cage systems according to the different hybrids in the regulation. This study aimed to investigate the effects of genotype (brown laying hybrids (BLH) and white laying hybrids (WLH)) and cage type (conventional and enriched cages) on behaviours of hens at the 90% egg production level. Behavioural data were recorded with video cameras during the 4 days. Data were analysed in 6 time periods as 05.00-08.00 am, 09.00-12.00 am, 01.00-04.00 pm, 05.00-08.00 pm, 09.00-12.00 pm and 01.00-04.00 am. Behaviour inspection each hour was divided into 4 quarters and the first 3 min of each quarter were evaluated. Behaviours were represented as the proportion of the total behaviour performed in the time period by a given hen. There was no interaction between hens' behaviour and the genotype at the same egg production level. The frequency of feeding behaviour was found to be significantly lower (P < 0.01), but comfort behaviour was higher (P < 0.05) in hens that were reared in the enriched cages. Only preening was seen as a comfort behaviour due to the cage size. The feeding, drinking, pecking hen, comforting, walking, sitting, resting and perching behaviours changed during the day (P < 0.01). Especially, the transition from light to dark influenced the perching behaviour negatively. No interactions were detected amongst genotype, cage type and time period. Feeding behaviour decreased and the comfort behaviour increased in the hens that were reared in the enriched cages because there were materials that would exhibit different behaviours. Hens in the enriched cage could not suddenly adapt to the dark and light period. For this reason, transitions to light and dark periods in poultry houses should be provided gradually, as in natural life.

The Welfare Status of Hens in Different Housing Systems – A Review

The currently used poultry farming methods, which aim to maximise economic profit, are based on ever new technological solutions that improve flock management and increase bird performance. However, they do not always meet the natural needs of birds. Every housing method and technological solution currently in use is faced with some issues, such as social stress, adverse temperature/ humidity conditions, risk of zoonoses, and behavioural pathologies, which determine poultry performance and welfare. Disregard for animal welfare involves not only ethical but also practical aspects, because well-being and housing comfort translate into better weight gains, health and productivity of the birds. The studies reported here suggest that every production system, despite the many welfare-improving aspects, causes numerous behavioural, productivity and health abnormalities in laying hens. Therefore, further research is needed to identify various risk factors for the purpose of improving housing systems and increasing the welfare of hens.

Effects of Different Scratch Mat Designs on Hen Behaviour and Eggs Laid in Enriched Cages

Simple Summary

Enriched cages for laying hens must contain litter so that pecking and scratching are possible. This is typically provided using layer’s feed dispensed onto a scratch mat, however, there are no regulations on the size or materials of the mat. This study examined how different scratch mat designs and bird age affected behaviours on the mat at three times of day, and their influence on where eggs were laid and shell quality. The proportion of hens at the scratch mats did not increase during or shortly after the application of scratch feed, however, they were more likely to be foraging then. Most eggs collected were clean and laid in the nest. Of the small proportion of eggs that were cracked or dirty, the mat type did not affect dirty eggs, but eggs laid opposite the Big Dutchman mats were more likely to be cracked at 79 weeks of age than at any other mat type or age. There appeared to be no optimal scratch mat design (of those studied) and their use (during observations) was low, suggesting that mat designs were not major influencers on bird behaviour.

Abstract

Laying hens in the UK and EU must be provided with litter for pecking and scratching. In enriched cages, this is commonly provided by dispensing layer’s feed onto a scratch mat. Mats vary in design and size, which might affect hen behaviour and egg quality, since eggs are sometimes laid at the mats. We investigated if four different scratch mats (BD, K, V, Z) provided to hens in enriched cages resulted in differences in behaviour on the mats and external egg quality. Twenty-four 60-bird cages (6 cages/bank × 4 banks) with 2 mats/cage at one tier of a commercial enriched cage unit were used. Mats were allocated to cages in a balanced design prior to the flock arriving. Hens and eggs were studied at 30, 50 and 79 weeks of age, with three behaviour observations (before, during or after scratch feed application). The data were analysed by GLMMs or LMMs. The vast proportions of birds on the mats were standing (0.720) or sitting (0.250). Bird proportions on the mats were low overall and declined from 0.028 (30 weeks) and 0.030 (50 weeks) to 0.020 (79 weeks) (p < 0.001). The greatest proportion of hens were observed on Z (p < 0.001), which had the largest area, but relative to the available area least birds were on Z and most were on K (p < 0.001). Foraging was not affected by bird age or mat type but was greater at the second observation (p < 0.001). Most eggs were laid in the nest box and were clean. Clean eggs declined, and dirty eggs increased, significantly with age, particularly at the scratch mat (p < 0.001). Dirty eggs were not affected by mat design. Cracked eggs were highest at 79 weeks of age, particularly with BD mats (p < 0.001). Overall, scratch mat designs had minimal effects on behaviour (but few hens were seen there) and egg quality.

Welfare and performance of commercial laying hens in conventional California cages at different stocking densities

The present experiment was conducted to investigate the effect of different stocking densities on performance and welfare of commercial white leghorn hens (BV 300 strain) reared in conventional California cages. A total of 270 hens were divided into four stocking density groups, viz. 60 sq. inch/387 cm2 (T1); 75 sq. inch/484 cm2 (T2); 85 sq. inch/ 548 cm2 (T3) and 100 sq. inch/645 cm2 (T4) per bird with 18 replicates in each treatment. The experiment was conducted for a 20 week period under uniform standard management practices with birds fed on commercial layer diet. It was observed T3 and T4 group birds had highly significant (P<0.001) percentage of hen day egg production, higher egg weight, better feed conversion ratio, minimum cost of production per egg compared to T2 and T1 at the end of 20 week experimental period. Welfare indicators—Feather score was significantly best in T4 group birds when compared to T1 group, whereas gait score and immunity parameters was non-significant among all the birds reared at different stocking densities. Considering well-being and production performance, the present study confirms that commercial laying hens reared in conventional California cages provided with 85 sq. inch/548 cm2 space per bird gives better quality egg production without compromising birds welfare.

Effect of a Large-sized Cage with a Low Metabolizable Energy and Low Crude Protein Diet on Growth Performance, Feed Cost, and Blood Parameters of Growing Layers

Effects of a large-sized cage with a low metabolizable energy and low crude protein (LME-LCP) diet on growth performance, feed cost, blood biochemistry, and antibody response of growing layers were evaluated. A total of 668 one-day-old female Gushi chicks were randomly allocated into three different cages, namely, large, medium, and small cages, referred to as Group A, Group B, and Group C, respectively, and fed LME-LCP diets. A fourth group of birds raised in small cages and fed a standard diet (STD) was designated Group D i.e. the control. Equal stocking densities were maintained among the four groups throughout the experiment, from 50–20 birds/m². Large cages with LME-LCP diet (Group A) increased the shank length and girth as chicks grew, improved the activities of serum creatine kinase, and reduced serum triglyceride and cholesterol concentrations. The total feed intake in birds from Group A was higher than those from the other groups at every stage. The total cost (rmb/bird) of feed was 6.70% lower in Group A than that in Group D, which indicated the cost-effectiveness of large cages. In conclusion, large cages with LME-LCP diets have positive effects on body weight, shank growth, and serum biochemical indices of growing Gushi chicks, and can reduce feed costs.

Natural behaviours, their drivers and their implications for laying hen welfare

Some believe that farm animals need to be kept in conditions that provide ‘natural’ aspects in the animal’s environment and, thus, provide the opportunity for the animals to perform their full ‘behavioural repertoire’. Captivity may restrict either behaviours that animals have instinctive, intrinsic propensities to perform whatever the environment or behaviours that are elicited by deficits in the animals’ environment. Behavioural restriction may also thwart general motivation to seek variety and/or avoid monotonous conditions. Appreciating whether an animal suffers if deprived of the opportunity to perform natural behaviour requires, first, an understanding of how the behaviour in question is elicited and controlled, the effects of early experience and genetics on the behaviour and the behaviour of the species in the wild, and, second, the behavioural, physiological and fitness effects of deprivation of the behaviour. Housing laying hens in conventional cages compromises their behavioural repertoire, such as nesting in a nest box, dust bathing, perching and foraging, and the present review focuses on the welfare implications if these natural behaviours are thwarted in modern poultry production. A floor space of &lt;561 cm2/hen increases physiological stress, reduces egg production and increases mortality in laying hens. There is also evidence of behavioural restriction in terms of reduced wing stretching, leg stretching, tail wagging, locomotion, floor and object pecking and preening with floor space in the range of 542–750 cm2/hen. Preference and motivation research has indicated that laying hens value resources such as nest boxes for oviposition, substrates for foraging and dust bathing, and perches for roosting. However, there is no convincing evidence that deprivation of these resources results in physiological stress. Furthermore, apart from adverse effects of the absence of perches on bone strength, there is no evidence that deprivation of nest boxes, perches, and foraging and dust-bathing substrates results in reduction in fitness such as reduced egg production or health. Nevertheless, preference research has indicated that the opportunity to utilise these resources, particularly nest boxes, may elicit positive emotional states in laying hens. Therefore, it is important to understand both how motivated the animal is to choose an option or perform a behaviour as well as the consequences of depriving the animal of this opportunity.

Comparison of selected indices of internal environment and condition of laying hens kept in furnished cages and in aviaries

Biochemical and hematological examination of blood and individual assessment of the birds were performed in Lohman Brown laying hens at 45 weeks of age housed in different systems. The biochemical examination revealed higher (p < .01) corticosterone levels, creatine kinase, and aspartate aminotransferase activity and lower (p < .01) levels of lactate, triglycerides, albumin, calcium, and phosphorus in aviary hens compared to hens housed in furnished cages. Hematological examination of hens housed in aviaries revealed higher (p < .05) hematocrit, leukocytes, heterophils, eosinophils, basophils, monocytes, and H/L ratio. Furthermore, hens housed in aviaries had lower (p < .01) body weight than hens in furnished cages, they were worse feathered (p < .001), had more damaged combs (p < .05), and poorer physical condition (p < .01). In contrast, caged hens showed worse (p < .01) feather condition of the wings due to abrasion and claws due to overgrowth. The results have shown that the housing system has a significant impact on the internal environment and condition of birds and that housing in aviaries without taking into account the specifics of such housing may lead to significant stress and disturbance to the welfare of laying hens.

Effect of simple and low-cost enrichment items on behavioral, clinical, and productive variables of caged laying hens

Housing layers in battery cages is a practice still used by many countries but it has been criticized because of its influence on behavioral repertoire of birds. We investigated whether simple and affordable enrichment devices alone impact behavior, foot condition and performance of laying hens housed in conventional cages. Hens were divided into plain cages (CON), cages with perches (PER), and cages with tassels and scratch-pads (ENR), and parameters were evaluated before and after enrichment placement. After perch placement inactivity, drinking and competition for space reduced 35.6%, 40.8% and 70.3%, respectively, whereas social interaction increased 19.3%. Both modifications decreased locomotion (75.0% and 42.4% for PER and ENR respectively) and abnormal behaviors (62.5% and 43.9.4% for PER and ENR respectively). None of the performance variables were affected by ENR or PER. Thermography was more efficient than visual inspection in detecting subclinical bumblefoot, and it confirmed that PER reduced subclinical and clinical cases. Our findings indicate that perches increased welfare-related behaviors and foot health of hens, supporting the use of these inexpensive and highly adaptable alternatives for the enrichment of battery cages.