B. O. Hughes

The influence of strain and environmental factors upon feather pecking and cannibalism in fowls

Synopsis The relationship between strain, seven environmental factors and pecking damage was investigated. Strain of bird, housing system, light intensity and position effect had major influences, diet and group size had minor, while population density and brooding temperature had no appreciable effect on pecking damage. Relationships between pecking damage and social hierarchy, fear responses and body weight were also demonstrated. It is suggested that although particular “causative factors” may sometimes be of overriding importance, the problem should generally be viewed in terms of the interaction between an individual bird and its environment.

The preference of domestic hens for different types of battery cage floor

Synopsis Hens were presented with four different types of floor in two‐choice situations; they were generally indifferent to the nature of the floor but showed a significant preference for fine hexagonal mesh over coarse rectangular mesh and over perforated steel sheet. Oviposition preferences mirrored standing preferences. Gauge of wire seemed to have little influence; we suggest that an important factor is the number of points at which the birds foot is supported. The hens preferred the hexagonal mesh in spite of its gauge being so fine that wires parted during the experiment, resulting in potentially damaging holes. The findings indicated that welfare considerations are not necessarily incompatible with cage floor designs which minimise egg breakage; a very light floor may be as comfortable as a heavy, solid one.

Preference decisions of domestic hens for wire or litter floors

Abstract A light and a medium hybrid strain of laying hen were tested to determine whether they differentiated between, and showed any preference for, wire and litter floors. In method 1 they were given constant access to both wire (2.5 × 2.5-cm mesh) and litter, and were observed to see how their time was partitioned. Although individual birds displayed a strong preference for spending their time on one floor or the other, the selections of the group as a whole did not differ from random. Previous experience with either wire or litter floors did affect their preference, but neither feeding, strain of bird nor time of day influenced their choice. However, 88% of eggs were laid on litter. A strain difference in roosting preference was noted: the light strain tended to roost on wire, whereas the medium strain showed a slight inclination towards litter. In method 2, in which birds were given a choice between separate cages, once the selection had been made it was irrevocable for a period of several hours, after which birds were returned to their home enclosure. In this situation six out of eight hens preferred litter; two showed no preference. Neither strain of bird nor time of day had an effect, but birds coming from cages with wire floors showed a stronger preference for litter than those from pens with litter floors. These experiments showed that an apparent preference for a particular environment can be influenced by several factors, including the method of testing used.

The pattern of food intake in female Brown Leghorn fowls as recorded in a Skinner box.

Summary The validity of the Skinner box was assessed as a means of obtaining detailed records of feeding behaviour. Once the records were shown to be reliable, they were found to reveal the following features in the fowls feeding pattern: 1. Each bird exhibited a characteristic diurnal feeding rhythm. A consistent feature of these diurnal rhythms was a sharp decline in the level of food intake towards the end of the day. 2. There was no regular fluctuation in food intake with a periodicity between 20 min and 4 hr. 3. Feeding was not random but was concentrated into bouts. An attempt was made to assess how these bouts could be defined objectively as meals. Some birds showed clear-cut feeding periods which were easily recognizable as meals, while in other cases meals were less distinct. 4. Frequency distributions of lengths of intervals between meals and frequency distributions of meals sizes were constructed. Both types of distribution were basically of a negative exponential form, indicating that there is no characteristic size of meal or length of interval in fowls. Within birds, the two distributions were of similar shape, while there were considerable variations between birds. 5. Meal size was positively correlated with the length of the interval which followed it. 6. There were slight and inconsistent positive correlations between the size of meals and the length of the intervals preceding them. 7. From these facts a brief hypothesis concerning the control of food intake in the fowl was formulated.

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.

Low incidence of aggression in large flocks of laying hens

Abstract In a series of experiments to investigate the social relationships of domestic hens in large flocks the incidence of agonistic interactions was determined in a free range system with 700 birds and in a perchery system with ten 300-bird flocks. In both systems aggressive behaviour was infrequent and, in general, rates of agonistic interaction per bird per hour were markedly lower than those previously reported for laying hens kept in small to moderate group sizes. In the perchery, when the doors between adjacent pens of 300 laying hens were opened, previously separate flocks mixed together without any apparent evidence of increased aggression. This is in contrast to what has been reported for smaller groups, which when allowed to mix fought and failed to integrate. When sub-groups of six birds were taken from the large flocks and mixed in a separate pen with six birds from other flocks or from their own flock as a control, agonistic interactions were again rare in both conditions. It is proposed that, in general, there is no individual recognition in large flocks: birds do not recognise flockmates as ‘familiar’, nor birds from other flocks as ‘unfamiliar’. This apparent lack of social structure in large flocks may be a factor in minimising agonistic interactions between individuals, with a consequent low level of aggression compared with smaller groups where there is an established hierarchy.

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)

The effect of environmental factors on activity, selected behaviour patterns and “fear” of fowls in cages and pens

Synopsis The causes of feather pecking are closely linked with the nature of the environment in which the bird is kept. The object of this study was to assess the influences of group size, stocking rate and illumination intensity on general activity, preening, head shaking and “ fear ” responses and to relate these activities to feather pecking. In caged birds activity was increased by brighter light, by more space per bird and by more birds in a group; more preening was seen in birds housed at a lower density and no treatment had an effect on head shaking. “ Fear ” responses were greater in dim light and particularly when group size was large. Birds in pens appeared to lack completely “ fear ” responses to the stimulus used. In pens only stocking rate was varied; it had the same effect on activity as in cages. At higher stocking rates birds in pens showed more head shaking. The relationships between feather pecking, “ fear ” responses and general activity are discussed.

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.

Individual perching behaviour of laying hens and its effects in cages

1. ISA Brown hens were housed, from 18 to 71 weeks of age, as groups of 4 in cages with 675 cm2/bird. There were 7 treatments: control cages and 6 treatments with perches fitted across the rear of the cage. Five treatments had 450 mm wide cages, with perches made from hardwood, textured metal, smooth plastic, softwood and padded vinyl, and one treatment had a 600 mm wide cage, with a softwood perch. There were 4 cages in each of the first 6 treatments and 6 in the last. 2. Overall, birds spent about 25% of the day time on perches. Most time (28 to 41%) was spent perching on the 600 mm softwood perches. Among 450 mm perches, most time (25 to 30%) was spent on the softwood perch and least (13 to 23%) on the plastic; the results suggested that a slightly rough surface was preferred. Individual birds varied considerably in the proportion of day time they spent perching; this variation was relatively consistent over time. 3. Overall, the proportion of birds roosting on the perches at night was 85% in period 1; declined to 76% by period 6, probably because increased body size made it almost impossible for 4 birds to perch in the 450 mm cages. Birds roosting on the floor tended always to be the same individuals. 4. Damage to the soles of the feet was less in all treatments with perches than in control cages. It was least in 600 mm wide cages and showed a negative correlation with time spent perching, both within and between treatments. Long or twisted claws, in contrast, tended to be slightly worse in treatments where there was most perching. 5. Downgraded eggs tended to be slightly more frequent in cages with perches; the greatest proportion (cracked 1.4%, dirty 3.6%) was from the 600 mm wide cages, as a result of hens laying from the perch and a build-up of manure behind it. 6. Although problems remain the findings suggest that provision of perches is important for the welfare of hens; perch space should be sufficient to allow all birds to perch simultaneously.