Welfare Of Laying Hens Research Articles

Effects of stocking density, flock size and management on the welfare of laying hens in single-tier aviaries

1. Management practices, stocking rate and flock size may affect laying hen welfare but there have been few replicated studies in commercial non-cage systems that investigate this. This study used a broad range of physical and physiological indicators to assess the welfare of hens in 36 commercial flocks. 2. Six laying period treatments were examined with each treatment replicated 6 times. It was not possible to randomly allocate treatments to houses, so treatment and house were largely confounded. 3. Three stocking rates were compared: 7 birds/m2 (n = 2450), 9 birds/m2 (n = 3150) and 12 birds/m2 in either small (n = 2450) or large (n = 4200) flocks. In addition, at 12 birds/m2, in both small and large flocks, birds were subjected to either standard (SM) or modified (MM) management. MM flocks had nipple drinkers and no nest-box lights. 4. Bone strength, fracture incidence, heterophil:lympocyte (H:L) ratio, live weight, organ weights, serum creatine, serum osmolality, muscle pH and faecal corticosterone were measured on samples of birds at the end of the rearing period and at the end of lay. During the laying period, mortality, production and integument condition were recorded at regular intervals. 5 Birds housed at 9 birds/m2 had higher mortality than birds housed at 12 birds/m2 by the end of lay, but not higher than birds housed at 7 birds/m2. Birds housed at 7 and 9 birds/m2 had lower percent liver weight, and worse plumage condition than most of the 12 bird/m2 treatments. Modified management tended to improve plumage condition. There were no clear effects of flock size on the welfare indicators recorded. 6. At the end of the rearing period fracture incidence was almost negligible and H:L ratio was within a normal range. 7. By the end of lay fracture incidence was 60% and H:L ratio was high, with no treatment effect for either measure. This, together with information on faecal corticosterone, feather loss and mortality, suggests that the welfare of birds in all treatments was relatively poor by the end of lay.

Welfare, Health, and Hygiene of Laying Hens Housed in Furnished Cages and in Alternative Housing Systems

The aim of this review was to compare welfare, health, and hygienic status of laying hens housed in furnished cages and in alternative systems. In alternative systems (floor housing and aviaries), birds have more freedom of movement and a more complex environment than in furnished cages. However, housing birds in much larger flocks in alternative systems leads to an increased risk of feather-pecking. Furthermore, air quality can be poorer in alternative systems than in furnished cages. This can affect health and hygienic status. There are only limited data on a direct comparison between furnished cages and alternative systems. Therefore, there is a need for an on-farm comparison of welfare, health, and hygienic status in these systems.

On-farm assessment of laying hen welfare: a comparison of one environment-based and two animal-based methods

Methods available to assess animal welfare at farm level are based on a range of welfare parameters, which can be divided into two categories, environment-based and animal-based parameters. The first category describes features of the environment and management, which can be considered prerequisites for welfare. The second category records animals’ responses to that particular environment and management more directly. Objective of this study was to validate a mainly environment-based method, the animal needs index (ANI), with animal-based methods: behavioural observations and feather condition scores (FCS). The study was conducted on 20 commercial laying hen farms, 10 farms with battery cages and 10 farms with deep litter systems. During a 1-day visit on each farm, ANI was assessed, FCS was scored, and behavioural observations were performed. Instantaneous scan sampling and continuous focal sampling were used to assess the time spent on different behaviours and the occurrence of event behaviours. Data from behavioural observations and FCS were reduced with principal factor analysis. This resulted in two factors for each method. Significant positive correlations were found between ANI, on the one hand, and ‘movement’ and ‘comfort’, two factors from behavioural observations, on the other hand. A significant negative correlation was found between ANI and ‘wing damage’ (from FCS). The results of this study show that ANI is valid and sensitive enough to show differences in animal welfare between housing systems, whereas differences in welfare within housing systems cannot be shown. In conclusion, ANI is an appropriate method for assessment of laying hen welfare on a large number of farms with different housing systems.

Laying hen welfare standards: a classic case of ‘power to the people’

AbstractLegislation concerning laying hen welfare appears to be influenced more by public perceptions than by scientific and commercial evidence. This paper considers public understanding and power over the issue, and how welfare standards are structured. The usual objection to battery cages is that they do not provide enough space, but there seems to be ignorance of the fact that they were developed in order to improve the health of hens. Evidence is presented of more advantages than disadvantages with cage systems, and of the opposite with alternative (non-cage) housing. Why, then, does the public remain more concerned about just one of the Farm Animal Welfare Council's Five Freedoms — to display most normal patterns of behaviour — than about the other four? Arguably, the declared intent to ban battery cages in the EU in 2012 could not have been based justifiably on evidence in the European Commission Scientific Veterinary Committee's Report on the Welfare of Laying Hens. One therefore has to conclude that the decision to ban battery cages was taken for mainly political reasons, reflecting a belief that the majority of public opinion is against cages. Directive 99/74/EC will allow the use of ‘enriched cages’ after 2012, but, for political reasons, Germany intends to ban battery cages in 2007 and enriched cages in 2012. Following a recent public consultation on a possible similar ban on enriched cages in England, it was decided to defer a decision until after Directive 99/74/EC is reviewed in 2005. In one non-EU country, Switzerland, a national referendum led to a ban on battery cages in 1992. At present, there are ambiguities in minimum standards for different housing systems based on Directive 99/74/EC, which can be exploited by egg producers, sometimes at the expense of bird welfare. These concern stocking densities, the provision of claw-shortening devices, litter and perches, and the practice of beak trimming. They raise the question of the extent to which the structuring of welfare standards should represent a compromise between bird welfare, practicalities, public pressure and commercial interests.

Effect of Feed Structure on Performance and Welfare in Laying Hens Housed in Conventional and Furnished Cages

A small-scale experiment was conducted to examine layers' selection pattern of whole wheat (WW), protein concentrate (PC) and coarse shell meal (SM) throughout the light day. Consumption of all feed components increased prior to darkness. However, an interaction between SM and the other feed components was found (P<0.05), caused by a greater increase in SM consumption prior to darkness than WW and PC. This interaction is probably related to the requirement for calcium for eggshell formation. Energy (WW)/ Protein (PC) consumption ratio did not vary throughout the light day. In a large-scale experiment, a diet with 40% whole wheat incorporated into 3 mm pellets was compared with a complete diet, also as 3 mm pellets, but containing no whole wheat. Coarse shell meal was added in the feed trough for the experimental diet. These diets were examined in conventional 3-hens cages and two furnished cage systems. The hybrids LSL and Shaver 2000 were used. A tendency towards a lower (P=0.07) feed conversion ratio (FCR) was found in the experimental diet relative to the control diet. This may be a result of a better plumage condition for birds fed the experimental diet. Weight of gizzard and gizzard contents was higher among birds on the experimental diet. Self-selection of shell meal did not affect eggshell strength and legbone strength. Birds housed in furnished cages with 16 birds per cage unit showed higher (P<0.05) feed consumption than birds housed in furnished cages with 8 hens per cage and birds housed in conventional 3-hens cages. Egg production was similar in all cage systems, except for a tendency for lower (P=0.06) egg production in the 8-hens cages in the second half of the experiment period. Plumage condition was generally poorer (P<0.05) in the furnished cages than in the conventional 3-hens cages. Fewer comb lesions were found among birds in furnished cages, which may indicate less aggression in layers housed in furnished cages compared with conventional barren 3-hens hen cages.

Use of perches and nestboxes by laying hens in relation to social status, based on examination of consistency of ranking orders and frequency of interaction

Four groups of 15–19 adult ISA Brown hens were studied in pens to assess the relationship between social status and use of perches and nestboxes. This was to test the hypothesis that subordinate hens use these resources more by day, for avoiding dominants, but that dominants use perches more at night, for roosting. The experiment consisted of a 5-week pre-treatment period, when no perches were present, and a 4-week treatment period, when each group was tested with different perch treatments (No, Low, Medium, High). All groups were observed systematically in each week, when all interactions of three types (aggressive peck, non-aggressive peck, approach/avoidance) in a group were recorded by noting the instigator and recipient (from numbered wing tags) onto a matrix. Proportions of time that each bird spent using perches and nestboxes, by day and at night, were also recorded. The results indicate that social status of individual laying hens is relatively stable across time and can be based reliably on counts of either aggressive pecks or approach/avoidances, but not non-aggressive pecks. Aggressive pecks were the most frequent type of interaction observed, and were reduced by the presence of perches. Use of nestboxes, but not perches, was greater at night than by day. There were weak tendencies for perches, and to a lesser extent nestboxes, to be used more by lower ranking birds by day, but not at night. There was some evidence of increased use of these resources by higher ranking birds at night. It is concluded that provision of perches reduces bird density on the floor (where nearly all interactions occurred), allows subordinates a means of avoiding dominants by day, reduces frequency of agonistic interactions, and should thus benefit laying hen welfare.

The Edinburgh Modified Cage: Effects of Group Size and Space Allowance on Brown Laying Hens

Modified laying cages are being developed in a number of European countries in response to public and legal pressure for improvement of laying hen welfare. The Edinburgh Modified Cage (which has a perch, nest box, and dust bath) is one design which is practical for commercial production. The trial reported here was concerned with specifications including group size and space allowance. There were no major management problems during the year except for an outbreak of red mite which was successfully treated, and egg production was above breeders’ standards (with few downgraded eggs). Hens used the space and facilities well. For example, they showed settled nesting behavior and laid 94% of eggs in nest boxes. Their physical condition was also improved in several respects compared to control birds in conventional cages. A group size of five or fewer proved most suitable, with a space allowance of about 675 cm2/bird in the main part of the cage (915 cm2 including the nest box) for brown birds. Egg production will cost more in modified cages than in conventional cages, but less than free range.

Social Factors Influencing the Hierarchies of Small Flocks of the Domestic Hen: Interactions between Resident and Part-Time Members of Organized Flocks

Social Factors Influencing the Hierarchies of Small Flocks of the Domestic Hen: Interactions between Resident and Part-Time Members of Organized Flocks