A test system previously described by Blom et al (1993) was used to investigate the preference of the Mongolian gerbil (Meriones unguiculatus) with respect to light intensity in their cage, by comparing a standard transparent rodent cage with three cages darkened by either 25, 50 or 75 per cent. The ten animals included in the test spent most of their time in the cages that were darkened by 50 and 75 per cent, thus relatively avoiding the standard cage. Preference was mainly determined by visits longer than 15min and was therefore possibly associated with sleeping behaviour. Food and water consumption were not restricted to the preferred cages.

These results imply that gerbils should be housed preferably in cages that allow sheltering in relatively dark places. For this purpose, placing shelter objects in the cage should be considered.

A comparison was made of the behaviour of budgerigars housed singly in commercially available cages obtained from a pet supplier, and budgerigars housed in a group of six in a small aviary. Budgerigars housed in the aviary consumed significantly more food and were more active, performing more wing stretching and flying. Caged budgerigars performed significantly more vocalizations. When tested individually, aviary birds were more active in a novel test chamber and were significantly more likely to approach an unfamiliar bird. Cage birds were generally reluctant to approach an unfamiliar bird, but showed an increasing tendency to approach when allowed a longer period of familiarization. Pet budgerigars are commonly housed in isolation from conspecifics, with little consideration of potential effects on welfare. The aim of this study was to provide some initial information about the effects of social isolation on the behaviour of budgerigars.

Theoretical models are presented of the effects of space, facilities and group size on the behaviour of chickens at high stocking densities, with relevance for all animals. The appropriateness of each model is supported by published data, although such data are scant for some important variables. Freedom of movement is analysed by taking the area of a hen as 475 cm2 and finding the number of free bird spaces left at different space allowances. This provides support for current recommendations of a maximum of seven laying hens per m2 on deep litter, but suggests that a maximum for broilers of 34 kg/m2 unacceptably restricts freedom of movement. In cages, freedom of movement increases with space allowance per hen, and, for a given space allowance, with cage and group size. Nesting behaviour is analysed for synchrony, which decreases with group size. Perching and feeding are often synchronous and the space needed for these is determined by body width. Recommendations are derived for hens in furnished cages. The main part of the cage should be as large as possible; an absolute minimum of 600 cm2 per bird is suggested, but 675 cm2 per bird is probably the minimum practical. Perch and feeder space should be provided at 14 cm or more per bird, with a possible derogation for light hybrids to 12 cm. The number of nest spaces needed varies with the number of birds, with nest spaces being 300 cm2 each. These recommendations sum to a minimum of 800 cm2 per bird for groups of eight or more, 850 cm2 for groups of four to seven, and 900 cm2 for groups of three or fewer, plus litter area. Crowding is primarily caused by limited space allowance, but for a given space allowance it is worse in small enclosures and groups.

Conventional cages for laying hens have many disadvantages for welfare and there have been widespread calls for them to be banned. However, they also have advantages: in particular, they house the birds in small groups. Modified designs intended to reduce the disadvantages while retaining the advantages have included the get-away cage (providing perches and other facilities for up to 60 birds), but these designs have not yet had much success. The Edinburgh project on modified cages has adopted a stage-by-stage, systematic approach to cage design. Recommendations include increased area and height compared to conventional cages, and inclusion of a perch, a nest box and a dust bath. Current trials combine all these features in designs with commercial potential One remaining welfare problem is restriction of locomotion, with associated effects on bone strength However, alternative, non-cage husbandry systems for laying hens also have welfare problems, including those associated with large group sizes, and these problems may be worse than those in modified cages. Probably most important is the risk of cannibalism - or the practice of beak trimming to prevent it. Rather than banning cages, it might be more appropriate for legislation to specify the facilities which should be provided for laying hens.

In the current state of development of alternative systems, modifying cages for laying hens could on balance be more beneficial to welfare than banning them.

The aim of this study was to investigate whether there were differences in fearfulness between laying hens (Gallus gallus domesticus) housed in aviaries and in cages. The tonic immobility (TI) test was used to assess the fearfulness. Norwegian light hybrid White Leghorn hens were housed in battery cages and in three types of aviaries: the Marielund, the Laco-Volétage and the Tiered Wire Floor. Each system housed about 1,500 birds. Tests were performed on 50 birds per housing system at 70 weeks of age in one laying flock and at 30 and 70 weeks of age in the next.

At 30 weeks of age in the second laying flock, the duration of the tonic immobility response was unaffected by type of system. At 70 weeks, however, hens in cages showed tonic immobility of longer duration than hens in aviaries, in the first as well as in the second laying flock No differences in TI between hens from the three types of aviaries were found. The duration of TI did not correlate with plumage condition or body-weight, except for a longer duration of TI with poorer plumage condition in aviaries at 30 weeks. These results indicate that the fearfulness of hens in cages, as measured by the TI test, increased considerably with time. The lower fearfulness shown by hens in aviaries suggests that this important aspect of welfare is more secured in aviaries than in cages.

Research synthesis, using techniques such as meta-analysis to combine the results of a number of studies, is a particularly useful technique when there are multiple studies with conflicting results, or where there may be conflicting interests, and can serve to extract the maximum information from animal experiments. The effect of conventional cages and alternative housing systems on measures of production, behaviour, physical and physiological condition in laying hens is an important question that would benefit from research synthesis. We found that statistical constraints did not allow the usual methods of meta-analysis, so as a first step towards quantitative comparison, we used a simple vote-counting approach based on the treatment means. We counted the number of papers in which conventional cages or alternative systems had a higher weighted mean for various response variables. Egg production was higher in conventional cages than in alternative systems, though this effect was probably mostly confined to the comparison with multi-level indoor systems. Bones were stronger from hens kept in alternative systems than those kept in conventional cages. We confirmed previous reviews that birds show more comfort behaviour and possibly dustbathing (or vacuum dustbathing) behaviour in alternative systems, but aggressive pecking did not differ between systems. Perhaps surprisingly, mortality, feather pecking and body wounds were not found to differ between systems. The latter findings suggest that the chance of a mortality or cannibalism outbreak may be no greater in alternative systems than in cage systems, but it should be noted that our analysis did not consider the magnitude of the difference in mortality. In conclusion, the meta-comparison undertaken here supports some but contradicts other conclusions reached in qualitative reviews.

In recent decades, concern about rabbit welfare and sustainability has increased. The housing system is a very important factor for animal welfare. However, information about how different available housing types for female rabbits affect their health status is scarce, but this is an important factor for their welfare. Hence, the objective of this study was to evaluate the health status of female rabbits in five common housing systems: three different single-housing systems with distinct available surfaces and heights; a single-housing system with a platform; a collective system. Female rabbits in the collective and platform cages had greater cortisol concentrations in hair than those in the single-housing system with no platform. Haptoglobin concentrations and kit mortality rates during lactation were greater for the collective-cage female rabbits. The collective group had more culled females and more lesions than in the other groups. The main reasons for culling in all the groups were reproduction problems and presence of abscesses, and the collective group of females was the most affected. In conclusion, it appears that keeping females together in collective systems negatively affects their health status and welfare, while single-housing systems imply lower kit mortality rates during lactation and cortisol concentrations, and fewer lesions in female rabbits.

Historically, animal welfare has been defined by the absence of negative states such as disease, hunger and thirst. However, a shift in animal welfare science has led to the understanding that good animal welfare cannot be achieved without the experience of positive states. Unequivocally, the housing environment has significant impacts on animal welfare. This review summarises how cage and cage-free housing systems impact some of the key welfare issues for layer hens: musculoskeletal health, disease, severe feather pecking, and behavioural expression. Welfare in cage-free systems is currently highly variable, and needs to be addressed by management practices, genetic selection, further research, and appropriate design and maintenance of the housing environment. Conventional cages lack adequate space for movement, and do not include features to allow behavioural expression. Hens therefore experience extreme behavioural restriction, musculoskeletal weakness and an inability to experience positive affective states. Furnished cages retain the benefits of conventional cages in terms of production efficiency and hygiene, and offer some benefits of cage-free systems in terms of an increased behavioural repertoire, but do not allow full behavioural expression. In Australia, while the retail market share of free-range eggs has been increasing in recent years, the majority of hens (approximately 70%) remain housed in conventional cages, and furnished cages are not in use. Unlike many other countries including New Zealand, Canada, and all those within the European Union (where a legislated phase-out commenced in 1999 and was completed in 2012) a legislative phase-out of conventional cages has not been announced in Australia. This review came about in light of the current development of the Australian Animal Welfare Standards and Guidelines for Poultry in Australia. These standards are intended to provide nationally consistent legislation for the welfare of all poultry species in all Australian states and territories. While it is purported that the standards will reflect contemporary scientific knowledge, there is no scientific review, nor scientific committee to inform the development of these standards, and conventional cages are permitted in the standards with no phase-out proposed.

The housing and management of laying hens and their productivity has gone through enormous developments in the last century. Housing has changed from free-range systems, via battery cages to a variety of loose housing and different types of battery cages, and back to outdoor access systems. Although battery cages are still the main system used worldwide, the number of hens housed in aviaries and free-range systems has increased in Europe, Australasia and some parts of the USA, but aviaries and free-range systems are still considered a niche sector compared to caged housing. The following paper reviews how breeding and selection have responded to changes in housing and management and whether different types of housing require different breeding programmes and, more specifically, whether a dedicated breeding programme should be developed for aviary and free-range systems.

From the available literature it was concluded that broadening the selection goal in existing lines is the best option for breeding programmes to provide genotypes that are suitable for a range of housing systems.

The switch from keeping laying hens in a floor or free range system into a cage system led to a considerable change in the way that breeding and selection took place. In the past 40–50 years up to the present date, the increase in genetic improvement of the egg laying trait was substantial. However, cage-adapted populations of laying hens seem to have lost some of their abilities to an adequate performance when returned to the old floor\free range systems. The strong concentration of all parts of the poultry production has meant that less than 10 international breeding companies supply most hens for laying purposes in the world and they have very little interest in developing genetic material for the West-European region where there are marked consumer preferences for eggs produced in non-cage systems. A particular Danish line, of White Leghorn origin named “The Skalborg hen” seems to have survived during an era of cage production system and they seems to have a production potential at farm level.

There are many different characteristics of housing systems which affect the welfare of laying hens, particularly because welfare itself has many diverse aspects. When cause and effect relationships between systems and welfare are assessed, it is evident that no system currently under consideration is ideal. Of those priorities listed by UK authorities such as the Ministry for Agriculture, Fisheries and Food and the Farm Animal Welfare Council, all systems are likely to provide ‘freedom from hunger and thirst, adequate lighting and the company of conspecifics’. However, conventional cages are less likely than other systems to provide ‘freedom of movement, freedom from fear, comfort and shelter, suitable flooring and freedom to display most normal patterns of behaviour’. Alternative systems, though, often expose birds to the danger of disease, to aggression from dominant birds and to the risk of cannibalism or beak trimming to avoid it. Overall, welfare is compromised more in conventional cages than in well-run alternative systems, though welfare is more sensitive to poor management and to market forces in the latter. Problems in cages are also less likely to be alleviated by genetic selection than those in alternative systems. The ideal system for present-day stocks should combine the small group sizes found in cages with the freedom of movement and complex environment characteristic of alternative systems.

Whitefish (Coregonus lavaretus L.) larvae from Léman (= Lake Geneva) and Lake Bourget (France) have been successfully mass reared in tanks of 50-60 l when fed exclusively on dry experimental and commercial diets. In spring water at 10 °C for three initial densities (100-200-400/l) tested, the survival at 35 days fluctuated generally between 30 and 50%. The final number and biomass harvested has been improved by the use of higher water temperature (14 °C) or by stocking with high initial density (200-400/l) at 10 °C. In Lake Leman, temperature appeared to be the key factor controlling the results of coregonid larvae rearing in submerged illuminated net cages (6 m3) stocked with 50 000 yolk sac fry and harvested at the end of spring. The results fluctuated greatly when stocking was too early (middle of February to beginning of March). They were improved by delaying stocking, to the period "mid-Marc - carly April" for yolk sac fry or to "end of March-April" when fry prefed on dry diet were used.

The incidence of bone breakage and other traumas in end-of-lay birds at the time of slaughter have important welfare and commercial implications. The problem is greatest among birds from the cage system where injury and stress appear to be particularly associated with the process of removing the birds from their cages and subsequent handling. The bone strength of cage-housed birds, together with some physiological and behavioural aspects, are briefly considered. Suggestions are made for reducing the incidence of injuries during bird removal.

The objective of the work described is the introduction of cage system modifications that enable the birds to express a wider range of behaviours, while preserving as far as possible the main advantages of the system. Preference testing and motivational studies have been undertaken in the process of assessing the value of increased space provision, perches and nest sites of various kinds.

In Western Europe public awareness of ethical problems associated with farm animal production began to be seriously aroused in 1964 by the publication of Ruth Harrison's book Animal Machines. Although the restriction imposed by the battery cage system on laying hens was seen as a major cause for concern, it was not until the mid-1970s that applied research into improved or alternative production systems for laying hens began. Following initial smallscale trials in the UK on what became known as the ‘get-away cage’ the concept was developed, especially in Germany. Investigations were initiated into other alternatives, including aviaries, percheries and combinations of raised wire floors, and these continue in Denmark, the FRG, the Netherlands, the UK, Sweden and Switzerland. It has yet to be seen how far the benefits of such systems, chiefly the enhanced range of behaviours observed in the birds, can outweigh the disadvantages, especially the higher costs and some disbenefits, including feather pecking and cannibalism. Except where legislation forces the issue, as in Sweden and Switzerland particularly, the adoption of alternative egg production systems will depend on the willingness of consumers to pay a higher price for the product. Reference is also made to welfare problems associated with other classes of poultry.

Although the concept of the get-away cage for laying hens originated in the UK in the early 1970s, most development has been undertaken in other countries, particularly in the FRG at Celle. After a series of seven experiments, each involving =4000 hens, it is concluded that forms of the system which include nest boxes and perches are capable of supporting performance levels that are similar to those obtained from birds in conventional cages. Whilst extra capital and labour costs might be expected to be up to 5% above those for normal cages, real welfare benefits are believed to result from opportunities the birds have to express an enlarged range of behaviours.

Des alevins de Brochet (Esox lucius, L.) ont été élevés en cages immergées dans le lac de Pareloup, selon 4 rations de zooplancton et 2 mises en charge.La croissance, le rythme de prise alimentaire, le régime alimentaire et la sélection des proies, ont été étudiés pendant 16 jours de leur phase planctonophage.Quelles que soient leur taille et leur ration, les alevins sélectionnent activement les proies de taille comprise entre 400 et 800 µ. Bosmina longirostris représente 51 à 80 % des proies ingérées.Pour 16 jours d'élevage, la ration optimale est de 17 grammes de plancton par cage, pour une mise en charge initiale de 600 alevins/m3.