Air Quality in Three Types of Laying Hen Houses

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.

Although many factors affect the welfare of hens housed in cage and non-cage systems, welfare issues in cage systems often involve behavioural restrictions, whereas many welfare issues in non-cage systems involve health and hygiene. This review considers and compares the welfare of laying hens in cages, both conventional and furnished cages, with that of hens in non-cage systems, so as to highlight the welfare implications, both positive and negative, of cage housing. Comparisons of housing systems, particularly in commercial settings, are complex because of potentially confounding differences in physical, climatic and social environments, genetics, nutrition and management. Furthermore, some of the confounding factors are inherent to some specific housing systems. Nevertheless, research in commercial and experimental settings has indicated that hens in conventional and furnished cages have lower (or similar), but not higher, levels of stress on the basis of glucocorticoid concentrations than do hens in non-cage systems. Furthermore, caged hens, generally, have lower mortality rates than do hens in non-cage systems. However, the behavioural repertoire of laying hens housed in conventional cages is clearly more compromised than that of hens in non-cage systems. In contrast to conventional cages, furnished cages may provide opportunities for positive emotional experiences arising from perching, dust-bathing, foraging and nesting in a nest box. Some have suggested that the problems with modern animal production is not that the animals are unable to perform certain behavioural opportunities, but that they are unable to fill the extra time available with limited behaviours when they have no need to find food, water or shelter. Environmental enrichment in which objects or situations are presented that act successfully, and with a foreseeable rewarding outcome for hens by also providing regular positive emotional experience, is likely to enhance hen welfare. Research on cage systems highlights the importance of the design of the housing system rather than just the housing system per se.

Bacterial Contamination of Eggshells in Furnished and Conventional Cages

Effects of calcium diet supplements on egg strength in conventional and furnished cages, and effects of 2 different nest floor materials

Effects of Dietary Energy Content on the Performance of Laying Hens in Furnished and Conventional Cages

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.

The new legislation for laying hens in the European Union put a ban on conventional cages. Production systems must now provide the hens with access to a nest, a perch, and material for dust bathing. These requirements will improve the behavioral aspects of animal welfare. However, when hens are kept with access to litter, it is a concern that polluted air may become an increased threat to health and therefore also a welfare problem. This article reviews the literature regarding the health and welfare effects birds experience when exposed to barn dust. Dust is composed of inorganic and organic compounds, from the birds themselves as well as from feed, litter, and building materials. Dust may be a vector for microorganisms and toxins. In general, studies indicate that housing systems where laying hens have access to litter as aviaries and floor systems consistently have higher concentrations of suspended dust than caged hens with little (furnished cages) or no access to litter (conventional cages). The higher dust levels in aviaries and floor housing are also caused by increased bird activity in the non-cage systems. There are gaps in both the basic and applied knowledge of how birds react to dust and aerosol contaminants, i.e., what levels they find aversive and/or impair health. Nevertheless, high dust levels may compromise the health and welfare of both birds and their caretakers and the poor air quality often found in new poultry housing systems needs to be addressed. It is necessary to develop prophylactic measures and to refine the production systems in order to achieve the full welfare benefits of the cage ban.

This study was conducted to compare the effects of layout of furniture (a perch, nest, and sandbox) in cages on behavior and welfare of hens. Two hundred and sixteen Hyline Brown laying hens were divided into five groups (treatments) with four replicates per group: small furnished cages (SFC), medium furnished cages type I (MFC-I), medium furnished cages type II (MFC-II), and medium furnished cages type III (MFC-III) and conventional cages (CC). The experiment started at 18 week of age and finished at 52 week of age. Hens’ behaviors were filmed during the following periods: 8:00 to 10:00; 13:00 to 14:00; 16:00 to 17:00 on three separate days and two hens from each cage were measured for welfare parameters at 50 wk of age. The results showed that feeding and laying of all hens showed no effect by cage type (p>0.05), and the hens in the furnished cages had significantly lower standing and higher walking than CC hens (p<0.05). The birds in MFC-III had significant higher preening, scratching and feather-pecking behavior than in the other cages (p<0.05). No difference in nesting behavior was found in the hens between the furnished cages (p>0.05). The hens in MFC-I, −II, and −III showed a significant higher socializing behavior than SFC and CC (p<0.05). The lowest perching was for the hens in SFC and the highest perching found for the hens in MFC-III. Overall, the hens in CC showed poorer welfare conditions than the furnished cages, in which the feather condition score, gait score and tonic immobility duration of the hens in CC was significantly higher than SFC, MFC-I, MFC-II, and MFC-III (p<0.05). In conclusion, the furnished cage design affected both behavior and welfare states of hens. Overall, MFC-III cage design was better than SFC, MFC-I, and MFC-II cage designs.

Highlights Adapted CO2 balance improves ventilation rate prediction in poultry housing systems. Respiration quotient set to 0.9 (day) and 0.85 (night) enhances model accuracy. Adjusting the CO2 production rate (+18% day, +8% night) boosts model performance. Model accuracy declines with inlet-to-exhaust CO2 differences below 150 ppm. ABSTRACT. Assessing the environmental impact of poultry farms requires accurately determining ventilation rates (VR) while minimizing resource use. Accurate VR estimates are crucial for precisely evaluating emissions, making VR a vital factor in enhancing the sustainability of poultry production. This study aims to adapt and validate the carbon dioxide (CO2) balance method for VR prediction in laying hen houses. The adaptation was based on the CO2 balance method from the International Commission of Agricultural and Biosystems Engineering (CIGR), which considers variables such as the CO2 production rate of hens (PRCO2), animal activity (AA), and the respiratory quotient of laying hens (RQ). Data collected from an experiment involving laying hens in conventional cages (CC) under laboratory conditions were used to adapt the VR prediction model. The adapted model was validated under both laboratory and commercial conditions in three housing systems: conventional cages (CC), enriched cages (EC), and cage-free systems (CF). At the laboratory level, validation was performed using data from two studies conducted in the same controlled laboratory conditions but with different housing systems (the first in CF and the second in the three systems simultaneously). At the commercial level, validation was performed using data collected from 30 commercial farms in Quebec, Canada. The resulting adaptations included setting AA to 1, RQ to 0.9 during the day and 0.85 at night, and PRCO2 to 18% during the day and 8% at night. The adjusted model demonstrated an R2 of 0.63 for VR prediction when the difference between exhaled and inlet CO2 was less than 150 ppm. At the experimental level, all evaluated housing systems showed an R2 greater than 0.63 and an average RMSE of 0.35 m3 h-1 hen-1. At the commercial level, housing systems exhibited an average predicted R2 of 0.71 and an RMSE of 1.68 m3 h-1 hen-1. The adapted CO2 balance method presented good predictive values across laboratory and commercial experiments. Keywords: Airflow, Animal activity, Egg production, Gas production, Poultry building, Respiratory quotient.

1. This study investigated the effects of different housing systems on oxidative defence mechanisms, heterophil functions, cellular immune response and cytokine production in laying hens. One hundred and twenty laying hens were allocated into one of four groups: conventional cages, furnished cages, deep litter, and free range. 2. Housing system did not affect malondialdehyde concentrations and enzymatic antioxidant status. Ascorbic acid values were higher in deep-litter hens than in those in conventional cages and free range. 3. Phagocytic and chemotactic activities tended to rise in the deep-litter system, and oxidative burst was higher than in furnished cages. Cytotoxic T cells were decreased in furnished cages, both cytotoxic and helper T cells decreased in deep litter compared to free range. 4. The IL-2 and IL-13 expression was higher in deep litter than in conventional cages, and IL-6 expression was higher in furnished cages than in free range. 5. Housing system had no significant effects on the oxidative defence system; however, they affected heterophil functions, cellular defence mechanisms and cytokine production. The results suggested that breeders need to consider the housing system’s potential effects on immune defence responses while applying a breeding strategy appropriate for animal welfare and consumer demand.

In an experiment including 2400 layers, a diet with 40% whole oats incorporated into 3 mm pellets (experimental diet) was compared with a complete diet, also as 3 mm pellets, but containing no whole oats (control diet). These diets were examined in conventional 3-hens cages and two furnished cage systems with 8 or 16 birds per group including nest, perches and litter. The effects of diet, rearing condition and cage system on performance, plumage condition, comb lesions and rear body wounds were studied. Furthermore, the effect of feed structure on gizzard characteristics and interactions with access to litter during rearing and laying periods were examined. The hybrids LSL and Shaver 2000 were included in the experiment. Egg production was lower (P<0.05) in furnished cages than in conventional cages. No difference in plumage condition was found between diets, but a significantly poorer plumage condition (P<0.05) was observed with increasing group size. Also, the frequencies of rear body (P<0.05) wounds increased as the group sizes increased, while no such effect was observed for comb lesions. Higher (P<0.05) feed consumption was observed in furnished cages than in the conventional, causing a corresponding increase (P<0.05) in feed conversion rate (FCR). Higher (P<0.05) FCR was observed for birds fed pellets with whole oats than the control. Whole oats also increased (P<0.05) the weight of gizzard and gizzard contents. For LSL, better (P<0.05) plumage condition was found for birds reared on a deep litter floor compared to cage rearing. It was concluded that no beneficial effect of replacing high amounts of ground oats with whole oats was observed. Genotype and rearing method may interact with housing system.

<abstract> <b>Abstract.</b> Egg production systems have evolved in recent years. In the last two decades, laying hen production systems shifted from deep-pit housing system to manure belt housing system while, in the next decade, they will most likely shifted to furnished cages, non-cage (e.g. slats/litter or aviaries) or free range systems. It appears that no single housing system is ideal from an environmental point of view and a hen welfare perspective. A better understanding of those systems is a key factor in the identification of the environmental hot spots associated with laying hen production systems. The aim of the study was to measure and compare gas emissions, manure characteristics, and egg production from three cage layer housing systems: conventional cage, furnished cage, and cage-free aviary system. The experiment was replicated with 360 hens (Lohmann LSL-Lite) reared in twelve independent bench-scale rooms (mini-barn) during an 11-week period (23-34 weeks of age). The experiment was a completely randomized design with three housing systems and four repetitions. The experiment took place between February and May 2015. Unfortunately, gas emission results were not available at the time this paper was prepared. However, the paper presents a description of the three cage systems, the operating conditions, and the methodology used to measured gas emissions during the experimentation. Averaged NH₃ concentration measured in the aviary system were almost 16^th times higher than those of the conventional and furnished cages. Bedding as well as manure decomposition has contributed to NH₃ production. CH₄ and CO₂ concentrations were similar among the three systems. This research is part of a multi-phase project, including an analysis of the hen welfare by, among others, an assessment of the quality of eggs, blood tests, and an assessment of the behavior of hens in cages. A life cycle assessment approach, combined with an economic analysis, will later be used to compare environmental footprint of the different housing systems.

The EU ban on conventional barren cages for laying hens from 2012 has improved many aspects of laying hen welfare. The new housing systems allow for the expression of highly-motivated behaviors. However, the systems available for intensive large-scale egg production (e.g., aviaries, floor housing systems, furnished cages) may cause other welfare challenges. We have reviewed the literature regarding the health, behavior, production characteristics, and welfare of laying hens when exposed to ammonia in their housing environment. Concentrations of ammonia gas are commonly high in aviaries and floor housing systems in which manure is not regularly removed, whereas they are usually lower in furnished cages. High levels are found during the cold season when ventilation flow is often reduced. Ammonia is a pungent gas, and behavioral studies indicate chickens are averse to the gas. High concentrations of gaseous ammonia can have adverse health effects and, when very high, even influence production performance. The most profound effects seen are the occurrence of lesions in the respiratory tract and keratoconjunctivitis. There is also evidence that high ammonia concentrations predispose poultry to respiratory disease and secondary infections. We conclude that there are animal welfare challenges related to high ammonia levels, and that immediate actions are needed. Development of improved systems and management routines for manure removal and ventilation will be important for the reduction of ammonia levels and hence will contribute to safeguarding hen welfare.

Perch Arrangements in Small-Group Furnished Cages for Laying Hens

Effect of the housing system on shedding and colonization of gut and internal organs of laying hens with Salmonella Enteritidis