4.1. Housing
This study presented results of a cross-sectional survey on housing and management practices among 65 laying hen producers in Canada using furnished cages, single-tier, or multi-tier systems. This information can be used to better understand practices in these housing systems to increase farmer awareness of expected changes during the transition phase of the Canadian egg production sector. Recruitment through the provincial egg boards led to high response rates in the different provinces. It should be kept in mind that participation was voluntary, and data was collected using self-administered questionnaires, which could have biased the sample. However, the study sample included a large range of farms representing all major egg producing provinces and included a large range of farm sizes (i.e., companies and family owned farms) representative of laying hen farms in Canada. The majority of flocks were located in Alberta, British Columbia, Manitoba, Ontario, and Quebec, which are the major egg production provinces. It should be kept in mind that there are large differences in terms of climate across Canada [
14], which could have implications for management practices such as ventilation, litter management, and outdoor access.
At the time of the study, approximately 28% of farms in Canada had furnished cage (11%) and non-cage housing systems (17%) present on their farm (possibly in conjunction with conventional cage systems) [
15]. Our study sample therefore represented approximately 22% of those furnished cage and non-cage farms. Specifically, we received responses from around 22% of all furnished cage and 21% of all non-cage housing systems present in Canada at the time of the study [
15]. Between 2016 and 2017, the number of hens housed in systems other than conventional cages increased from 16% to 23%, totaling approximately 5.6 million out of over 24 million laying hens currently in production in Canada [
10,
16]. In context, farmers participating in this study filled in the questionnaire for approximately 935,000 laying hens, representing nearly 17% of all hens kept in furnished cage or non-cage housing systems. The majority of respondents were male and half of the respondents were under 45 years of age, which is a somewhat higher representation of young farmers, as close to 30% of egg farmers are under 45 years of age [
16]. Possibly, younger farmers were more likely to have furnished cage or non-cage systems and were more likely to participate in the study explaining this discrepancy. Additionally, the majority of farms had been working with these systems for more than one year (77.8%), while 22.2% had had their system for less than one year. This shows the current transition taking place in the Canadian egg production sector as also indicated by previous studies reporting that more than 90% of laying hens in Canada were kept in conventional cage housing a decade ago [
17]. It should be emphasized that this survey spanned these fast-paced changes in the sector, together with the launch of the new Canadian Code of Practice for the Care and Handling of Pullets and Layers [
11]. Some practices will be changing or will have changed already, as approximately half of the flocks were placed before the Code of Practice came into effect (placement of flocks occurred between October 2016 and December 2017).
The majority of flocks were kept in furnished cages which is likely due to the simpler conversion of conventional cages to this housing system compared to non-cage systems. Fitting into the farm and consumer demands are important factors when choosing new housing systems during the transition period [
18,
19]. A survey among over 800 consumers in Vancouver, British Columbia, showed a strong increase in consumption of cage-free specialty eggs i.e., 32.9% free range eggs, 11.9% organic eggs, and 7.6% free-run eggs in 2009, compared to a combined consumption of 8% of cage-free specialty eggs in 2007 [
20]. This finding shows increased consumer demand for cage-free eggs. While there are some regional differences in consumer preferences and willingness to pay [
21,
22], it is likely that food trends occurring across Canada such as the use of cage-free eggs in restaurants and more specialized, individual choice in grocery stores will increase and this plays a role in shaping consumer behavior [
8].
The recently updated Code of Practice for laying hens in Canada provides interim and final requirements for aspects such as space allowance, nesting, perching, foraging, and dustbathing [
11]. Approximately 45% of the flocks in the study were placed in the laying facilities before the Code of Practice came into effect, which could explain why not all practices conformed with requirements set out in the Code at the time of the study. For example, the range of calculated space allowances suggests that all flocks were not yet housed in line with the transitional requirements of 580.6 cm
2/hen for furnished cages [
11]. The space allowances calculated for non-cage housing systems should be considered as approximations; not all useable space (e.g., vertical space in the tiers) was accounted for. Similar to furnished caged flocks, some flocks in non-cage systems did not yet meet the transitional requirements (929.0–1115.0 cm
2/hen depending on perch space provided). However, average space allowance reveals similar values to the final space allowances required in the Code of Practice [
11] and the 750 cm
2/hen space allowance for furnished cages and stocking density of 9 hens/m
2 (1111.1 cm
2/hen) for non-cage systems as set out in the European legislation [
1]. It would be interesting to investigate drivers and barriers in uptake and compliance with the new Code of Practice requirements in flocks placed after the transitional date.
Nearly half of the flocks in furnished cages were not provided with a scratch area, possibly due to being installed prior to when the Code of Practice came into effect [
11]. These type of cages are generally considered cages with furnishings or enrichable cages and will need to be updated to meet the final requirements of furnished cage housing systems in order to provide a flooring surface for foraging and/or dustbathing [
11]. Similarly, over 20% of the non-cage systems did not provide any litter but rather had a fully slatted barn, a practice which is no longer allowed under the Code of Practice [
11], in comparison to 3.3% of flocks in Switzerland [
23]. In contrast, 34 barn and free range layer farms in Australia all reported to use slatted flooring [
6], showing large differences in flooring types in different countries. Additionally, the time at which studies were conducted should be kept in mind, as, for example, the Swiss study was conducted between 1997 and 1998 [
23] and should be interpreted with caution as the current conditions in the sector are likely different. In the majority of farms that provided litter, at least one-third of the barn was covered with litter, which is in line with European legislation [
1]. While few specific recommendations on the management of litter substrate are available, indicating that litter must be of good quality and friable [
11], our findings show most farmers do not break up or replace the litter after first access. Factors such as proper barn climate and functioning drinkers, which minimize water spillage, can help ensure litter stays friable [
24,
25,
26]. Litter depth averaged around 5 cm but ranged from 0.5 to 12.7 cm. According to a survey on laying hen farms in Switzerland, over 80% of flocks were provided with more than 3 cm of litter when 2–3 months after lay, while 21% showed a maximum depth of more than 10 cm [
23]. While no figures are available on optimal litter depth, Huber-Eicher and Sebö [
27] recommended to use a lower litter depth in general. Instead, they suggested to regularly supplement with new litter to avoid problems with litter getting into the feeder and to keep the foraging substrate attractive to the birds [
27]. Additionally, large litter depths can increase the risk of floor eggs which can be managed through adaptations in rearing to allow birds to find and use nest boxes early on [
26]. While it is unclear whether farmers added fresh litter or broke up the litter substrate during lay, 94 out 170 laying hen farmers in the UK reported that there was no loose litter at the end of the laying period [
24]. This shows the importance of litter management, and by extension barn climate, in order to ensure that litter provision can fulfill its function as a foraging and dustbathing substrate throughout the laying period. Of the farms that provided litter, nearly a quarter listed manure as the substrate. While litter is a defined as a combination of bedding and manure that builds up over time and therefore is allowed under the Code of Practice, it could be argued that only providing manure without additional bedding material should not be considered normal practice [
11,
25] and is contradictory to consumer expectations and so can influence public perception of litter-based systems [
28]. Recently, von Waldburg et al. [
29] showed that laying hens prefer to feed and forage in substrates free of manure. However, when no other options for foraging material are available, laying hens spend more time foraging on scratch pads soiled with manure [
30], suggesting that manure as a litter substrate is preferred over no litter substrate at all. It is important to consider though the implications the presence of manure in a system can have in terms of egg contamination, foot disorders, and animal or worker health in relation to ammonia [
31].
Manure removal from the system occurred at least 1× per week in furnished cage and multi-tier systems, likely due to the ease with which automatic manure belts can be operated. Manure removal occurred less frequently in single-tier systems, especially when the system was a fully slatted barn. These systems often have a manure pit that is only cleared out at the end of the flock. Frequent manure removal can prevent ammonia concentrations from reaching harmful levels, and higher ammonia levels have been recorded in single-tier systems compared to free range and furnished cage systems [
32]. Laying hens prefer environments with fresh air over environments with ammonia concentrations of 25 ppm [
33]. However, further investigation is required to determine how frequently manure should be removed to avoid these aversive concentrations. Interestingly, Garner et al. [
34] found that the number of eggs/hen-housed increased when manure was removed in conventional cage systems during the laying period, suggesting that frequent manure removal can have positive implications not only for worker and animal welfare but also flock productivity.
Little variation was observed in laying hen feeding practices. The majority of flocks were fed mashed feed through chain feeders. Flocks were fed between 2 to 12 times per day (mean: 5.5 times per day), similar to a previous study that reported that the majority of flocks were fed 6–7 times per day [
35]. Diet changes were a common occurrence on most farms which was related to the age of the flock, with flocks having undergone more than three diet changes by the time they reached approximately 48 weeks of age. This is largely in line with common breed guidelines [
36,
37]. Midnight feeding where lights are turned on during the dark period to encourage feed intake can be used to improve egg shell quality [
38]. However, turning on the lights during the dark period can also influence sexual maturity, and this practice is generally not recommended for pullets [
39]. Additionally, this practice is not allowed in all countries for laying hens. In fact, the European directive 1999/74/CE requires that laying hens have 8 h of uninterrupted darkness every 24 h, which would be disrupted when applying midnight feeding [
40]. Similarly, feeding animal by-products was not common, likely due to the potential consequences it can have on food safety and human health [
41].
The hours of light per day offered was relatively constant between flocks and the little variation found can be explained by the large age range of the flocks. Light intensity was similar to the recommended 5–15 lux in the breed guidelines [
36,
37]. However some farmers reported less than 5 lux, and nearly a quarter of farmers could not estimate the lux. A dawn/dusk period was provided in the majority of flocks. Gradual dimming of lights by area was especially used in multi-tier systems, which encourages birds to perch during the night [
42].
4.2. Flock Characteristics
The majority of breeds included in the study flocks were Dekalb White, Hy-line Brown, ISA Brown, Lohmann Brown, and Lohmann LSL. However not all respondents were able to identify the specific strains. There was an equal distribution of white- and brown-feathered flocks, with white-feathered flocks being more common in furnished cages, while brown-feathered flocks were mostly kept in non-cage systems. Brown-feathered birds lay eggs with brown shell color. Such eggs are perceived by consumers to have a higher nutritional value as well as an association with naturalness, which could explain consumer preference for brown over white eggs [
20,
43,
44]. This perception could further contribute to the use of brown-feathered birds in non-cage housing systems, although breed suitability to the housing system should be considered [
45].
All flocks were beak trimmed at day-old, which is a standard practice in order to reduce feather pecking problems [
13]. However, beak trimming is under scrutiny and does not reduce feather pecking completely if flock management is not adequate [
13]. Another important consideration is the housing system used during rear. In order for flocks to perform successfully during lay, it is recommended to rear pullets in a similar system to that used during lay [
45]. This provides birds with opportunities to learn appropriate behaviors (e.g., access to litter, perches, nest boxes) that reduce behavioral problems (e.g., floor eggs, feather pecking) and can improve productivity and reduce mortality [
26,
46,
47]. Most pullet housing systems at the time of the survey were conventional cage systems [
15]. Currently there are only few furnished cages for rearing pullets available on the market. In this study, laying hen flocks housed in furnished cages typically originated from conventional cage systems (one flock from furnished cage rearing facility), with the exception of two flocks that were reared in a single-floor system. Janczak and Riber [
48] indicated that aviary-reared pullets should not be subsequently housed in furnished cages, however this recommendation was based on small furnished cages housing a maximum of 9 birds. More recent work investigating the effect of aviary-rearing for hens subsequently housed in large 30- or 60-bird furnished cages found few detrimental effects and several benefits to aviary rearing compared to conventional rearing [
49]. Nearly 95% of flocks in single-tier (1 flock from conventional cage rearing facility) and 100% of flocks in multi-tier systems were reared in the same system as they were housed in during lay. It is important to note that the majority of flocks in non-cage systems were reared by layer producers, giving them greater control over rearing facilities and possibilities to match conditions between rear and lay, while the majority of flocks in furnished cage systems came from a rearing supplier.
On average birds were inspected 2–3× per day by 1–2 workers on the farm. In comparison, Louton et al. [
35] found that 44% of farmers inspected their flock 1 time, 27.2% 2 times and 14.4% 3 times per day. The amount of time spent on inspections in our study was similar to previously reported durations with most farmers spending up to 30 min per inspection [
35]. Self-reported practices such as disinfection of barns and use of dedicated clothes and/or boot dips were common. Only a limited number of farmers claimed to have developed and implemented a flock health plan with their veterinarian and veterinarian visits to the farms were generally rare. Poultry farmers in Australia reported similar practices with veterinarian visits occurring once per year or only when a health issue occurred [
6]. Higher stocking densities and more frequent bird-to-bird contact in furnished cage and non-cage systems are considered a risk for increased pathogen density and subsequent disease, especially in suboptimal housing and management conditions [
45,
50]. In spite of this, prevalence of disease in the study flocks was low, likely due to stringent vaccination schemes used on-farm (data not shown). Following the ban on conventional cages in Switzerland, Kaufmann-Bart and Hoop [
50] found a decrease in viral diseases over a 12 year period, while bacterial diseases tended to increase. They emphasized the importance of vaccination, farm hygiene, and effective biosecurity in maintaining good health in laying hens in non-cage systems and concluded that health levels were comparable to those observed in caged housing systems [
50]. Cumulative flock mortality was below 6% in all study flocks, which is in line with findings by both Louton et al. [
35] and by the European Food Safety Authority [
45], who found that mortality in the majority of flocks was below 10%. The mortality rate was highest in multi-tier systems, followed by single-tier and furnished cage systems. Birds in furnished cages typically show lower mortality rates compared to those in non-cage systems [
32,
51]. However, this is dependent on the age and genotype of the birds, management, and disease risk [
45].
Flock performance and egg productivity are dependent on the flock age. In this cross-sectional study, flocks were observed at different stages of lay making comparison between flocks difficult. However, 50% rate of lay and peak production observed in these different flocks were comparable to those stated in the breed guidelines [
36,
37]. Birds in non-cage systems showed a higher feed consumption and lower productivity compared to furnished caged birds as reported in previous studies [
45,
47,
52]. This was, however, confounded by strain since the majority of furnished caged flocks were white-feathered, whereas those in non-cage systems were brown-feathered birds.