Poultry housing and husbandry.

1. In order to conduct this anniversary review, 10 excellent papers were carefully selected from the 148 available papers published on housing and husbandry in British Poultry Science (BPS) over the past 50 years. 2. The 10 selected papers on this subject covered mainly the housing and husbandry of laying hens, but two of them dealt with various aspects of broiler production. 3. Aspects of housing considered included a wide range of intensive and extensive systems of broiler and egg production. Specific topics included the effects of husbandry system on bird welfare, including skeletal damage in laying hens and contact dermatitis in broiler chickens, as well as the design and management of nest boxes, perches, feeders and drinkers, conventional laying cages (CCs), furnished laying cages (FCs) and non-cage systems (NCs). 4. A variety of the findings in these and related papers have enlightened our understanding of many aspects of poultry housing and husbandry; most of them have found application in the poultry industry and thus improved its efficiency.

Evaluation of the effects of cage height and stocking density on the behaviour of laying hens in furnished cages.

1. Limited information is available on how changes in horizontal and vertical space within enriched or furnished layer cages (as defined by Directive 1999/74/EC) influence hen behaviour. This study evaluated the effects of varying minimum cage heights and space allowances on the behaviour of laying hens housed in furnished cages. It was conducted on two flocks of medium brown hybrid hens housed in furnished cages with access to perches and nest boxes on a semi-commercial scale at ADAS Gleadthorpe. 2. Flock 1 consisted of two layer strains (ISA Brown and Babcock 380), housed at two minimum cage heights (38 and 45 cm) and 5 stocking densities between 609 and 870 cm2/bird, with 12 replicates of each of the 20 strain/cage height/stocking density treatment combinations. Stocking density was varied by varying the number of birds per cage from 10 to 7 in standard full-width cages or housing 7 hens in a narrower cage. As a consequence stocking density, group size and trough width per bird co-varied for 4 out of 5 stocking density treatments. 3. Behaviour of flock 1 was sampled at 33 to 36, 46 and 68 weeks of age. At each age one top-tier, one middle-tier and one bottom-tier cage was sampled for each treatment. 4. Few behavioural differences due to cage treatments were detected. Hens at 870 cm2 had shorter feeding bouts than hens at 609 and 762 cm2. Yawning was more common in the cages with greater cage height. 5. Video recordings of flock 1 examined cage height effects on hens' use of vertical space and provided additional data on stretching and self-maintenance activities. No differences in behaviour between 38 and 45 cm cages were found except that scratching head was more common in cages with greater cage height. 6. Flock 2 consisted of two layer strains (Shaver Brown and Hy-Line Brown), housed at 38 and 45 cm and 609, 762 and 1016 cm2/bird, with 18 replicates of each of the 12 strain/cage height/stocking density treatment combinations. Stocking density was varied by housing 10, 8 or 6 hens in standard full-width cages. Behaviour of flock 2 was sampled at 30, 48, 60 and 67 weeks from video recordings. Three cages per treatment from middle-tiers only were sampled at each age. 7. Hens housed at 609 cm2/hen had the longest mean feeding bout, greater than for hens at 762 cm2/hen but not hens at 1016 cm2/hen. More unsuccessful attempts to reach the feeder and sideways and backwards displacements from the feeder occurred at 762 and 609 cm2/hen than at 1016 cm2/hen. A maximum of 8 hens were observed feeding synchronously. 8. These results suggest that changes in horizontal and vertical space over the ranges we studied had little effect on behaviour other than feeding behaviour. Specifying a minimum useable trough space per hen, rather than calculating feeder space from total length of feeder per cage, irrespective of accessibility, might help avoid crowding at the feeder and associated disturbance of feeding bouts.

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.