Behaviour and welfare.

1. We have chosen papers which we feel are representative of important subjects which have been covered by the Journal over a period of 50 years. We would not claim that these are objectively the best papers, for that is a matter of personal judgement, but we consider that they have made significant contributions to knowledge and understanding in poultry behaviour and welfare. 2. John Savory has selected 8 papers from Volumes 1-25 of British Poultry Science (1960-1984), which deal with 5 different aspects of behaviour and welfare: embryonic responses, feather pecking and cannibalism, cage floor preferences, lameness in broilers and myopathy in turkeys. 3. Barry Hughes has selected 11 papers from Volumes 26-50 (1985-2009) of British Poultry Science. Four topics been chosen: broken bones in layers, furnished cages, interaction of birds with machines, and stocking density and bird space.

Development of furnished cages for laying hens.

1. A 3-year trial was carried out of cages for laying hens, occupying a full laying house. The main cage designs used were 5000 cm2 in area, 50 cm high at the rear and furnished with nests and perches. F cages had a front rollaway nest at the side, lined with artificial turf. FD cages also had a dust bath containing sand over the nest. H cages had two nest hollows at the side, one in front of the other. They were compared with conventional cages 2500 cm2 in area and 38 cm high at the rear. 2. Cages were stocked with from 4 to 8 ISA Brown hens per cage, resulting in varied allowances of area, feeder and perch per bird. No birds were beak trimmed. In F and FD cages two further treatments were applied: nests and dust baths were sometimes fitted with gates to exclude birds from dust baths in the morning and from both at night; elevated food troughs, with a lip 33 cm above the cage floor, were compared with standard troughs. 3. Management of the house was generally highly successful, with temperature control achieved by ventilation. Egg production was above breeders' standards and not significantly affected by cage design. More eggs per bird were collected when there were fewer birds per cage but food consumption also then tended to be higher. 4. The number of downgraded eggs was variable, with some tendency for more in furnished cages. Eggs laid in dust baths were often downgraded. Those laid at the back of the cage were frequently dirty because of accumulation of droppings. H nests were unsuccessful, with less than 50% of eggs laid in the nest hollows. However, up to 93% of eggs were laid in front rollaways, and few of these were downgraded. 5. Feather and foot damage were generally less in furnished than in conventional cages, greater where there were more birds per cage. With an elevated food trough there was less feather damage but more overgrowth of claws. In year 2, mortality was greater in cages with more birds. 6. Pre-laying behaviour was mostly settled in front rollaway nests. Dust baths were used more for pecking and scratching than for dust bathing. Comfort behaviour was more frequent in furnished cages than conventional, although still not frequent. Locomotion was strongly affected by number of birds per cage or by space per bird, being reduced by crowding. Most birds perched at night except in one treatment providing only 10.7 cm perch per bird. 7. Behaviour was more unrestricted and varied, and physical condition was better, in furnished than in conventional cages. However, egg production will cost more in furnished cages, partly because more eggs are downgraded. Dust baths must be fitted with gates that the birds cannot open from outside, but gates for nest boxes were found unnecessary. If a low perch is fitted it must be far enough from the back of the cage for birds to walk there. 8. Where there was less space per bird (more birds per cage) than the requirements in the 1999 European Commission Directive on laying hens, there were: fewer eggs per hen, but still above the breeders' target; lower food consumption; more feather and foot damage, but less than in conventional cages; higher mortality in one trial out of three; less freedom of movement. However, the results were still very good even with 8 birds per cage, and support the principle that furnished cages provide an acceptable way of protecting the welfare of laying hens.

Spatial distribution and behaviour of laying hens housed in an alternative system.

The spatial distribution and behaviour of perchery housed laying hens were compared at a constant stocking density (18.5 birds/m(2)) in eight pens with colonies of five different sizes (323 birds (N=1), 374 birds (N=2), 431 birds (N=2), 572 birds (N=1) and 912 birds (N=2)). The birds were placed in the perchery when they were 12 weeks old. Observations began when they were 26 weeks old and continued at 8 week intervals until 61 weeks of age. Colony size did not appear to affect the spatial distribution of birds, but more standing behaviour and less feeding behaviour were observed in the smallest and largest colony sizes. Older birds spent more time on the floor areas and less time on perches. Young birds (26-28 weeks) spent more time feeding, foraging, drinking and preening, and less time standing idle than older birds. In the afternoons, there were fewer birds on the perches and more on the floor levels, corresponding with less time spent resting and more time spent performing active behaviours. Birds did not distribute themselves evenly throughout their pens: within specific areas of pens densities varied between 9 and 41 birds/m(2). This variation, which reflects the flux of birds from one part of the pen to another, was greatest for the larger colony sizes, and may have adverse implications for welfare in terms of crowding and hysteria.

Laying hens in large flocks in a perchery system: influence of stocking density on location, use of resources and behaviour.

1. ISA Brown laying hens (3000) were housed in a perchery in 10 pens, each with 300 birds. The pens varied in size to produce 4 different stocking densities: 9.9 birds/m2 (n = 3), 13.5/m2 (n = 2), 16.0/m2 (n = 2) and 19.0/m2 (n = 3). Observations began at 20 weeks of age and continued until 69 weeks to establish the spatial distribution of the birds, usage of the different resources and the expression of behaviour. 2. Overall, birds spent most time on the perch frame (47%), litter area (23%), slatted floor (17%) and nestbox area (9%). 3. There was no effect of density on the proportion of birds observed on the slatted floor or on the elevated perches but as density increased the proportion on the littered area decreased. 4. Space usage was determined vertically, horizontally and longitudinally. Individual birds were seen to use about 80% of the pen volume available to them. This value was similar for all densities and showed that individuals did not have separate home ranges. 5. Fewer vertical movements were made within the main perch frame at the upper than at the lower levels but movements between the perches of the main frame and the nestbox rails were relatively frequent. This may help birds move up and down through the main frame. 6. Behaviours which decreased in incidence with crowding included moving, foraging and dust-bathing. Behaviours which increased with crowding included standing. Behaviours which were unaffected included resting, preening, prelaying behaviour, comfort behaviour and the minor behaviours. 7. The proportion of birds engaged in feeding and drinking was unaffected by density, except each time the chain feeders (which operated intermittently) ran more hens were seen feeding at the lower densities. This suggests that food delivery stimulated feeding behaviour; there may have been some restriction at the higher densities on birds feeding when and where they wanted. 8. Stocking density had no effect on the frequency of agonistic interactions: threats, lunges, comb/head pecks, chases and fights. 9. The incidence of damaging pecking was low and not density dependent. 10. Increasing density within the range investigated inhibited the expression of a number of behaviours and limited the use of specific resources: bird welfare at 19 birds/m2 may have been very slightly impaired.

Ability of laying hens to jump between perches: individual variation and the effects of perch separation and motivation on behaviour.

1. This study investigated the ability and the behaviour of laying hens jumping between perches 2 different distances apart using hungry and satiated birds to determine whether behaviour and success were related to motivation. 2. Four groups of 10 birds (Lohmann brown) trained to jump from one perch to another were subjected 4 times to each of the experimental treatments (2 perches with a distance of either 50 or 150 cm between them) whilst either hungry or satiated, controlling for time of day and order of presentation. 3. The behaviour of each bird on the 1st perch was observed for a maximum of 2 min or until the bird jumped from the perch. The outcome of each jump, number of head movements and steps, incidence and duration of calling, and activity score were recorded. 4. The probability of birds jumping was less at the greater distance and was not affected significantly by other experimental factors. 5. Head movements were more frequent in birds which jumped, at the shorter distance, in motivated (hungry) birds and in the morning rather than the afternoon. 6. More stepping was performed by birds which jumped and at the shorter distance; there was no significant effect of motivation or time of day on stepping rate. 7. Birds called more at the greater distance and this was interpreted as indicative of frustration. 8. Subjective scores for activity were lower when perches were separated by the greater distance and when birds were satiated (less motivated) rather than hungry. 9. Agitated head movements and stepping activity thus occurred mainly when birds were motivated and on the point of jumping whereas calling was associated with an apparent inability or unwillingness to jump.

Factors affecting the use of perches in cages by laying hens.

1. Three experiments were carried out with ISA Brown laying hens housed in individual cages with softwood perches of rectangular cross section fitted across the width of each cage, to investigate factors affecting the tendency of hens to lay their eggs from the perches and to use perches at other times. These factors were perch width and angle and method of perch introduction. 2. In experiment 1 there were 4 treatments. Perches were 38 or 60 mm wide; half of each width were flat and half were fixed at 8 degrees, parallel to the slope of the floor. In 2 similar trials (with 48 and 44 birds respectively, equally divided between treatments) birds were moved to experimental cages already fitted with perches. Birds with 38 mm, sloping perches laid less than one third of their eggs from the perch (31% and 9% in the two trials) while those with the other designs laid more than 80% from the perch. Narrow sloping perches were not otherwise aversive and there was no consistent variation between treatments in total time perching. 3. In experiment 2, 32 birds were allowed to start laying on the floor of the experimental cages then perches were introduced at 24 weeks with 8 birds on each of 4 treatments: 50 mm perches fixed flat and 38 mm perches fixed flat, and at 5 and 10 degrees respectively. Only 27% of eggs were laid from the perches with no variation between treatments either in this behaviour or in total time perching. 4. Experiment 3 provided 24 of the birds from experiment 2 with double-length perches to determine whether they showed preferences for the design features under consideration. Either half the perch length was flat and half sloping at 10 degrees or half was 38 and half 50 mm wide. Again a relatively low proportion of eggs was laid from the perches (18%) and birds showed no significant preference for different perch designs as indicated by either how much they perched or where they perched. 5. These results suggest that both perch design and the way pullets are introduced to perches influence the proportion of perch-laid eggs. They confirm that in some circumstances laying from perches can be a serious problem, but that in other circumstances incidence can be reduced to a manageable frequency. Perches may therefore be practical in commercial production without increasing the number of cracked eggs. The results are also likely to be applicable in cages with other facilities including nest boxes.

Egg shell colour is affected by laying cage design.

1. When laying hens are stressed some retain their eggs in the shell gland beyond the normal time of laying and this can result in the deposition of extra-cuticular calcium which makes brown eggs appear paler. 2. Three different types of enriched modified cage were compared: the location where eggs were laid was recorded and shell colour was measured using a reflectometer. 3. In 2 types of cage with enclosed nest boxes more eggs (80%) were laid in the nests than in a design with nest hollows in the open part of the cage (41%). 4. The eggs from the cages with enclosed nests were darker (had less extraneous calcium) than those with open nest hollows. This implies that in the designs with nest boxes fewer eggs had been retained and the hens may have been less stressed. 5. The results support previous evidence that to reduce stress and improve welfare it is desirable to provide enclosed nest sites for caged laying hens.

Comparison of food intake, rate of consumption, pecking activity and behaviour in layer and broiler breeder males.

1. The food intake, rate of food consumption (g/min) and behavioural time budgets of individually caged broiler and layer (white egg) males were compared in the early morning (1.5 to 3.5 h after onset of photoperiod) and afternoon (5.5 to 7.5 h after photostimulation) on 4 different days at 11 to 12 weeks of age. Correlations among rate of consumption, the proportions of time on different activities and previously estimated scores for fearfulness were calculated. 2. Food intake and rate of consumption were two-fold greater in broilers than in layers. The proportion of time spent feeding in the morning was lower in layers compared with broilers and was similar in the afternoon. Rate of consumption was higher in the morning than in the afternoon in both lines. 3. Overall, a similar proportion of time was spent feeding, standing and sitting in both lines. The birds were more likely to be sleeping (eyes closed) in the afternoon than in the morning. 4. The proportions of time spent on preening, pecking and stereotypic pacing were greater in layers than in broiler breeders. The proportion of time spent drinking tended to be higher in broiler breeders than layers. 5. Two measures of fearfulness, aversion to a looming human and a novel rod were respectively positively and negatively correlated to time drinking and stereotypic pacing. 6. The time spent in stereotypic pacing was negatively related to rate of consumption and time spent preening. 7. The results suggest that low food intake is associated with increased arousal, fear and frequent feeding and drinking. There was no evidence that beak related activity was related to fearfulness.

Behavioural and anatomical consequences of two beak trimming methods in 1- and 10-d-old domestic chicks.

1. To examine the effects of beak trimming on behaviour, beak anatomy, weight gain, food intake and feather condition 360 ISA Brown chicks were trimmed by hot cut or cold cut at 1 d or 10 d of age or were sham-operated controls. The experiment was a 3 x 2 factorial design, with the chicks housed in littered pens in groups of 10 and observed for 6 weeks after trimming. 2. In the first week after trimming, when trimmed birds were compared with untrimmed controls, they were less active (sat and slept more), fed less, preened less and generally engaged in less beak-related behaviour. 3. These differences waned sharply during week 2 and had disappeared by week 5. There were very few differences between hot- and cold-cut birds. 4. There were also differences in production variables: trimmed birds grew more slowly during the week after trimming, their food intake was depressed for 3 weeks and food conversion efficiency improved for 2 weeks. 5. The only significant effect on feather scores was better plumage condition in the groups trimmed at 1 d and scored at 6 weeks. 6. To examine the anatomical effects 36 ISA Brown chicks trimmed by hot or cold cut at 1 d or 10 d of age were killed at 21 and 42 d after trimming, and their beaks were processed and examined histologically. In all trimmed groups healing was very rapid and no scar tissue was seen but, unlike the controls, the regrown tips contained no afferent nerves or sensory corpuscles. 7. Beak lengths immediately after trimming were 40% to 50% shorter than controls; the anatomical consequences of both methods were identical. 8. Overall, it was judged that the effects on behaviour and beak anatomy were much less severe than previously reported for birds trimmed at older ages. If birds do have to be trimmed then the procedure should be carried out in young birds: from the birds' standpoint 1 d appears to be the most suitable.

The Edinburgh modified cage for laying hens.

1. Behaviour, production and welfare of ISA Brown medium hybrids were assessed in 2 trials (each from 20 to 44 weeks of age) of a novel design of cage for laying hens: the Edinburgh Modified Cage (EMC). 2. The EMC was 600 mm wide, 450 mm deep and 450 mm high at the rear; it had a softwood perch and at one side a 250 mm wide nest box (containing litter or artificial turf) with a dust bath directly above. It housed 4 birds and provided 675 cm2/bird in the main cage with an additional 281 cm2/bird in the nest box. The nest box and dust bath had automatically controlled doors which were closed at night. There were 18 EMC; in the first trial these were compared with 6 control cages with perch but without next box or dust bath. 3. Hens spent 32 to 37% of day time on the perch, 5 to 7% in the dust bath and 5 to 6% in the nest. At night 92 to 98% roosted on the perch. 4. Initially only 55 to 70% of eggs were laid in the nest box partly because some eggs were laid before dawn. Once the door was retimed to open 3h before lights-on the proportion rose to 91 to 96%. Very few eggs were laid in the dust bath. Pre-laying behaviour lasted longer in treatments with nest boxes (55 to 76min) than in control cages (48min); disturbance was slight in all treatments, but lowest in control cages. 5. Dust baths were well used, with on average 61% of hens dust bathing during a 3-h afternoon observation period compared with only 17% in control cages. Two birds could use the dust bath simultaneously. 6. It was concluded that although a number of minor design features still required attention the EMC has potential to reduce the disadvantages of conventional cages for welfare while retaining their advantages and has possible commercial application.

An experimental investigation of the costs and benefits of beak trimming in turkeys.

An investigation was carried out on 504 BUT 8 female poults to identify the optimum technique and age for beak trimming breeding turkeys, which have to be kept at relatively high light intensities and are thus at serious risk of cannibalism. Different groups of birds were subjected to electronic trimming (Bio-beaking) at one day old, cold cutting (with secateurs) at six days or at 21 days, or hot cutting (with a cautery iron) at six days or 21 days old. The behaviour, production traits, feather damage, injuries and mortality of the birds were measured up to 12 weeks old. None of the methods had much effect on the behaviour or production traits, other than relatively minor reductions in beak-related activities such as pecking other birds and preening, and short term depressions of food intake and bodyweight gain, and improvements in food conversion ratio. All the beak-trimming techniques resulted in marked reductions in mortality (controls 8.7 per cent, trimmed 1.6 per cent), in injuries due to cannibalism (controls 68.1/100 birds, trimmed 9.8/100 birds) and in the scores of feather damage caused by pecking (controls 1.05, trimmed 0.29). The adverse effects of beak trimming were minor and short-lived, and were clearly outweighed by the benefits in reducing cannibalism. Of the different methods, trimming with a hot blade is not recommended. Electronic trimming appeared to offer the most benefits and caused little apparent distress, but can be hazardous in unskilled hands.(ABSTRACT TRUNCATED AT 250 WORDS)

Anatomical consequences of partial beak amputation (beak trimming) in turkeys.

A detailed anatomical study was made of the effects of trimming the upper beak of turkeys. The anatomy of the normal beak was compared with that of beaks from birds which had been trimmed by one of three methods, all commonly used in the poultry industry: the Bio-Beaker which passes an electric current through the premaxilla, secateurs, or a heated blade debeaker. All three resulted in the loss of significant amounts of beak tissue. By 42 days after trimming the beak had healed with extensive regrowth, including bone and cartilage formation, and the pattern of regrowth was similar after all three methods. In the normal bird the dermis at the tip of the upper beak contains large numbers of nerve fibres and sensory receptors, but in the beak-trimmed birds the dermal tissue, although well supplied with blood vessels, was devoid of afferent nerve fibres and sensory nerve endings. In contrast with the results of previous studies with older chickens there was no evidence of neuroma formation. Trimming with secateurs was the most precise method. The heated blade damaged additional tissue close to the position of the cut, and the BioBeaker produced the most tissue damage. Behavioural studies suggested that the effectiveness of beak trimming in controlling feather pecking depends on the extent of the tissue damage.

Current state of poultry welfare: progress, problems and strategies.

This article supplements the published Proceedings of the 4th European Symposium on Poultry Welfare. It presents an overview of the conclusions of the Symposium and of the workshops and plenary discussions of the papers. The four main topics reviewed were: Basic Biology and Welfare, Welfare Criteria in Alternative Systems, Welfare of Turkeys, Waterfowl and Other Species, Welfare of Broilers.

Nesting, dust bathing and perching by laying hens in cages: effects of design on behaviour and welfare.

1. Laying hens (192 ISA Brown medium hybrids) were housed from 18 to 72 weeks as groups of 4 in conventional or experimental cages. The main area of all cages provided 675 cm2/hen. All experimental cages had perches, dust baths and nest boxes, which were of three types: litter (L), artificial turf (A) or plastic rollaway (P). These facilities provided an additional 375 to 480 cm2/hen. The nest boxes and dust baths occupied either high or low positions. Behaviour, physical condition and production of the birds were regularly recorded. 2. Mortality was low (1.6% overall) and egg production very good in all treatments. The proportion of cracked and dirty eggs was slightly (but not significantly) higher in the experimental cages. In the experimental cages 90% of eggs were laid overall in the nest boxes and 3% in the dust baths. The proportion laid in the nest boxes was lower early in the laying cycle and increased with time, reaching 99% in A. 3. The facilities were heavily used. Birds spent about 25% of day time on the perches and 10-15% in or near the nest box and dust bath. At night, the majority of birds (90 to 94%) roosted on perches, but most of the remainder were on the lips of the nest box or dust bath, fouling the interiors. 4. Pre-laying behaviour was much more settled in the experimental cages (45 min spent in the eventual laying position) than in the conventional ones (20 min) and total duration varied from 68 min in A to 87 min in P. The number of nest entries varied from 3.0 (A and P) to 4.3 (L); disturbance to sitting birds was correspondingly greater in L. 5. Dust bathing in the experimental cages generally took place during the afternoon in a single bout of about 5 min duration, whereas in the conventional cages it was brief and fragmented (3 bouts of 10 s each). The dust bath was also used for foraging behaviour (pecking and scratching). The treatments with small dust baths (A and P) caused problems for the birds. 6. Feather, foot and claw damage all tended to be less in the experimental than in the conventional cages, though only in the last case was the difference significant. Keel bone depressions appeared to be associated with perches; they were present in 43% of hens in the experimental cages but only 4% in conventional cages.(ABSTRACT TRUNCATED AT 400 WORDS)

Comparison of bone volume and strength as measures of skeletal integrity in caged laying hens with access to perches.

Fractures in spent laying hens are now recognised as a major welfare problem; the objective of this work was to determine whether provision of perches for caged layers would increase bone strength, bone volume or both. Sixteen ISA Brown hens were housed from 18 to 72 weeks old in cages with perches and 16 in similar cages without perches. At the end of lay the birds' tibiotarsi were examined for strength by a three-point loading test and their tarsometatarsi for bone volume by histomorphometry. There was no significant effect of perches on tibiotarsal breaking strength. Hens from both groups showed evidence of osteoporosis, but it was more severe in the birds from conventional cages: tarsometatarsal trabecular bone volume was greater in the hens which had access to perches. A positive correlation was found between trabecular bone volume and the degree of day-time perch usage by individual hens. Provision of perches can have a slight but significant beneficial effect, at least for the leg bones, in increasing the bone volume of caged laying hens.

Effects of perches on trabecular bone volume in laying hens.

Trabecular bone remodelling is known to be affected by loading or exercise, and thus exercise may effect the trabecular bone loss associated with osteopenia in laying hens. Sixteen ISA Brown hens were housed from 18 to 72 weeks old in cages with perches and 16 in similar cages without perches to examine the effects of the exercise afforded by perch provision on trabecular bone volume. At 72 weeks, mean trabecular bone volume in the proximal tarsometatarsus of birds with access to perches was significantly greater than in control birds, while medullary bone volume was not significantly different in the two groups. However, all the birds were considered osteoporotic, though to varying degrees, and the beneficial effects of perches were relatively minor. It was concluded that while trabecular bone loss may be reduced by perch provision, other factors are probably more influential in the development of the osteoporosis typical of laying hens.