I tive svstems that can offer improvements in

81999 Applied Poultry Science, Inc EFFECT HOUSING HEALTH, RESPONSE IN LAYERS OF TWO FLOOR SYSTEMS AND CAGES ON PRODUCTION, AND FEAR RAGNAR TAUSON', ANNSOFIE WAHLSTROM, and PER ABRAHAMSSON Depament of Animal Nutrition and Management, Funbo-Lovsta Research Center, Swedish University of Agricultural Sciences, S-755 97 Uppsala, Sweden Phone: + 46(0)1&674500 FAX: + 46-(0)1&674501 E-mail: Ragnar. Tauson@huv.slu.se Primary Audience: Researchers, Veterinarians, Flock Supervisors DESCRIPTION OF PROBLEM Criticism of COnventional age keeping of laying hens focuses on the lack of possibilities for birds to perform behaviors such as nesting, lack of space [l, 2,3]. The search for alterna- I tive svstems that can offer improvements in these respects has been going on for the last 20 yr, especially in northwestern Europe [4,5]. However, hygienic problems, the risk of para- 1 To whom correspondence should be addressed

Research Report TAUSONetal. 153 ment created by higher dust levels, increased emissions of ammonia, and collection of floor eggs, as well as the risk of outbreaks of cannibalism in large flocks of birds, have been negative factors in litter floor systems [6, 7, 8, 91. Beak trinl.:aing as one means of reducing pecking among birds is under intensive discussion [lo, 11,121 and has been banned in some countries, including Finland, Norway, and Sweden. Pecking leading to intensive feather loss and/or cannibalism is the main problem when keeping hens in large flocks where the social structure is more difficult to establish than in small groups. The large group in itself results in more individuals being affected than in small group cages. Long-term studies under practical conditions have clearly demonstrated the difference in both cannibalism and production depending on whether beak trimming is used [13, 141 or not [l5, 16, 171. Pecking appears with great unpredictability and is affected by both housing conditions and genetics [18, 191, as well as by feed composition [20]. Non-beak-trimmed medium-heavy brown hybrids in multi-tiered aviary systems may be especially subject to very high mortality rates due to cannibalism, as well as poor feed efficiency caused by heat loss through areas of the skin exposed by feather pecking [8]. Most recent studies on floor systems have focused on multi-tiered aviary systems characterized by considerably higher stocking densities per ground floor area than traditional litter floor management provides. Apart from the problem of pecking, great variations in the proportion of mislaid eggs in aviary systems have been reported [20]. The misplacement of eggs seems especially common in the mediumheavy hybrids, which seem less attracted to the nests and also less mobile in tiered systems. Because aviary systems are a recent development, there is little information from controlled studies on differences in bird performance and behavior in aviaries as compared with the traditional litter floor system with slats. In practice, the latter system is much more common in countries with a considerable amount of the laying stock kept on litter, e.&, Denmark, France, Great Britain, the Netherlands, and Sweden. Reports from field observations indicate that the low stocking density systems of traditional design yield fewer problems typical of large-group housing environments than do the higher stocked aviary systems. The objective of this study was to compare health, production, and behavior in birds of two different hybrids kept in a traditional litter floor system, in an aviary system, and in cages. The study was carried out between April 1996 and June 1997. MATERIALS AND METHODS BIRDS, REARING, AND FEED Two genotypes were used: LSL (Lohmann Selected Leghorn) and LB (Lohmann Brown). The birds were vaccinated against Marek s disease, AE, and coccidiosis and reared from day-old in two separate pens at the same rearing farm, without getting their beaks trimmed. A two-tiered aviary system was used, with the chicks kept for the first 5 wk on the wire tiers with feed and water. Thereafter and until 16 wk of age they also had access to a floor litter area beside the tiers. The second tier had perches installed. They were given an ordinary growers mash without coccidiostats until 17 wk. Pullets were transferred to the experimental building at Funbo- Lovsta Research Centre at 16 wk. From 17 wk until the age of 80 wk they were given a layers diet in crumbles containing 2.60 Mcal ME/kg, 15.1% crude protein, 3.5% calcium, 0.58% phosphorus, 0.71% lysine, and 0.40% methionine. All feed was provided ad libitum. HOUSING, STOCKING, AND LIGHTING Three housing systems were used and installed in the same experimental building: 144 conventional three-hen cages (C), four pens of the Marielund three-tier aviary system (M) as described by Abrahamsson and Tauson [6], and four pens of a traditional floor housing system (T) (Fienhage) with one tier of a manure bin covered with solid plastic sloping net and elevated perches at 0.2 and 0.4 m. The litter area with wood shavings constituted an aisle of 1.2 m alongside the tier(s) in the aviary and 1.5 m in the other floor system. All systems had automatic endless manure belts under each wire floor. Elevated flat chain feeders were placed on the wire floor/slats except on the top tier in the aviary. Egg collection was carried out by hand in the cages and by belts from individual Facco plastic bowl nests in the aviary and by hand from Astroturf colony rollaway nests in the traditional floor system. Nests were placed on the wall in three tiers

154 HOUSING AND HEALTH opposite the wire tiers in the aviary and at the upper end of the plastic floor area in the traditional system. The lowest tier in the two systems was placed at 0.5 m in the aviary and at 0.45 m in the traditional system. Pen size was 2.80 x 5.80 m in the aviary and 4.55 x 3.10 m in the traditional system. In the cages, three birds were housed per cage at 640 cm2 floor area per hen for both LB and LSL. In each of four pens of M and T, 245 LB and 285 LSL and 117 LB and 117 LSL buds were housed, respectively. This implied 15.1 LB and 17.9 LSL and 8.3 LB and LSL buds per m2 ground floor and 7.7 LB and 9.1 LSL and 8.3 LB and LSL per m2 available area, respectively. Altogether, there were 432 birds in the cages, 1060 in the aviary, and 234 in the traditional floor system equally distributed among the two genotypes. In the cages, there were three replicates per treatment (genotypes x housing system) comprising 72 hens in each. In the aviary and the traditional system there were two replicates (pens) per treatment. To allow birds to use the litter during their entire stay in the system, ix., during the initial weeks of maturation, they were not fenced in on the slatted floor area in T In practice, confinement on the slats, i.e., where the nests are placed, is a common procedure in traditional litter floor systems in order to facilitate the finding of nests, feed, and water in order to reduce the number of floor eggs (those in the litter). At 16 wk the birds were given 9 hr of daylight, which was increased by half an hour per week, up to 14 hr/day at 25 wk. Incandescent light bulbs were used for all systems, including a sunrise/sunset light program. RECORDING AND COLLECTION OF DATA The study covered the period from 20 to 80 wk of age. All data were collected per replicate and eggs were collected daily and weighed once a week. Egg production was calculated as kg eggmass per hen housed at 20 wk (eggm./hh) and as percent laying and g eggmass per live hen day (eggm./hd) over the whole production period. Feed consumption was recorded daily and calculated for the entire production period. Egg quality, expressed as the proportion of dirty and cracked eggs, was recorded every eighth week, comprising all eggs produced in 2 days. Eggs were transported to a commercial packing plant where eggs from each replicate were graded and candled separately. On two occasions, at 35 wk and 55 wk, the live weight of the hens was recorded and their integument and health scored using the method of Tauson et al. [21], assigning a score of 1 to 4 points for condition of foot (claws, foot pads, and digits), with plumage of six body parts pooled into one total, yielding a maximum score of 24 points and a minimum of 6 points. Pecking or scratching wounds around the rear part of the body and on the comb were also an element of the scoring. Tonic immobility (TI) as a fear response is suggested by Jones and Faure [22] as a useful tool when providing guidelines for future research on animal welfare. TI was tested on randomly selected birds, 20 from each aviary replicate, 9 from each replicate of the traditional system, and 6 from each replicate of the cages - a total of 152 birds. It was induced by placing each bird on its back and restraining it for 15 sec in a wooden V-shaped cradle covered with a dark blue towel, with the head hanging outside as described by Jones and Faure [22]. The operator held one hand over the bird s breast and the other hand covering the head [23]. Time from catching until the bird was placed in the cradle was approximately 60 sec. The number of inductions necessary to induce the TI and the duration of TI, i.e., time elapsed until the bird righted itself, were recorded individually [22]. Maximum duration time was set to 1500 sec. All dead birds were autopsied at the National Veterinary Institute, Uppsala. These findings were expressed as means for each treatment and in percentage of housed birds with a certain finding. Statistical analyses were performed with an ordinary analysis of variance, using the General Linear Models of the Statistical Analysis system of SAS [24] where hybrid and housing system were considered fued. Before analysis, the traits given in proportions (mortality, misplaced eggs, and egg quality) were subjected to arcsin transformation [W]. For exterior egg quality, the weighted means for the registration periods were used.

Research Report TAUSONetal. 155 TABLE 1. Production, mortality, tonic immobility, and egg quality in light white Leghorn (LSL) and medium-heavy brown (LB) hens in three housing systems (M =aviary; T =traditional floor; C = three-hen cages) at 20-80 wk of age HOUSING RESULTS AND DISCUSSION PRODUCTION AND MORTALITY Results of production, including live weights and mortality, are given in Table 1. Significant differences (P <.OOl-.OS) were found in almost au production and mortality traits between housing systems and hybrids and in interactions between them. Nonsignificant effects were found only in egg weight between housing systems and in interactions between housing systems and hybrids for live weight at 55 wk, for proportion of dirty eggs, and for egg weight respectively. In general, the brown medium-heavy LB genotype showed inferior production traits, including feed consumption and mortality rates, compared with the light white LSL hybrid. However, there was a very strong effect of housing system in the former genotype. While LSL were unaffected by housing system, the LB very clearly demonstrated a negative reaction in the large group floor environments compared to the three-hen cages. An increase in mortality starting at about 40 wk, ranging up to more than 20% at 80 wk in the floor systems, was observed. The problems with peckinghmibalism in LB buds in aviaries agrees well with recent reports [6,8,16,20]. Although banned in some countries, eg., Sweden, beak trimming when carried out on day-old chicks as proposed by Gentle et al. [ 111 probably would have considerably reduced mortality in the sensitive LB birds. The possible negative effects of trimming the beak of layers, such as pain, behavior, or sensory deprivation, have to be balanced against the hazards and welfare problems that may show up in non-beak-trimmed birds, such as cannibalism/pecking as described by Hughes and Gentle [lo] and Hunton [12]. The poor insulating effect of large naked areas in the LB floor hens also yielded inferior daily feed consumption and FCR, in agreement with Tauson and Svensson [26] and Peguri and Coon [27$ Production results and FCR for LB in cages were similar to those of the LSL hens and better than the latter in the traditional system, again illustrating the nonbeak-trimmed LB genotype to be better suited for smaller group sizes, and thus a more stable social order. Apart from the LB hen being heavier than the LSL hybrid, the LB hens showed a higher live weight in the cages than in either floor system (P<.02 at 35 wk and

156 HOUSING AND HEALTH P c.06 at 55 wk). This indicates that LB birds were more active in these systems and possibly, if the higher level of pacing to escape from peckers is taken into account, also more stressed. In the face of extensive heat losses, LB hens evidently could not achieve enough extra feed intake to maintain weight in the floor systems, in contrast to the caged birds, which may even have over-consumed feed. EGG QUALITY Proportions of misplaced eggs as given in Table 1 differed si&icantly between housing systems (P c.03) and hybrids (P c.02). There was also a significant interaction effect (P c.os). The proportions were generally acceptable and below 1% except for the LB in the aviary system, which had a higher rate of 5.4% (P<.Ol). This is in agreement with Abrahamsson et al. [SI as well as with Wahlstrom et al. [20], who also used the threetiered Marielund aviary system and mediumheavy hybrids. These birds seem very clearly less attracted to nests, or alternatively are not prepared to search for nests at different levels, which is necessary in a multi-tiered system, in contrast to traditional floor systems. In contrast, the LSL hybrid showed low proportions of misplaced eggs regardless of complexity in the design of the floor system. Misplaced eggs were found mainly on the sloping wire tiers in the aviary and on the floor and slats in the traditional floor system. At the higher rates of misplaced eggs it was assumed, and also partly observed, that these eggs were subjected to pecking and thus were unable to be collected. The proportions of cracked eggs differed between housing systems (P <.Ol) and hybrids (P c.001). An interaction effect (P c.01) was also found. There were differences in proportions of dirty eggs between both housing systems (P.: -01) as well as hybrids (Pc.04). Egg quality traits such as cracks and dirties did not differ significantly between housing system for LB, but for LSL both cracked and dirty eggs were fewer in the traditional floor system than in either the aviary or the cages. The higher proportion of dirty eggs in LB compared with LSL was probably an effect of more misplaced eggs registered in M for the former hybrid. In both hybrids, the T housing with colony nests yielded the lowest average proportion of dirty eggs. Nest design and hy- giene, proportion of misplaced eggs, litter condition, and dry matter content of manure may all affect egg quality traits. Obviously, it is possible to achieve a very low proportion of cracked eggs with the LSL hens in the traditional system compared with both an aviary and cages. HEALTH The results of the scoring of integument and condition of body parts are given in Table 2. At 35 wk there were signrficant effects of housing system on condition of plumage (Pc.05), bumble foot, and foot hygiene (P <.OOl), claws, keel bone deviation, plumage hygiene (Pc.Ol), and comb wounds (P c.04). A significant effect of hybrid was also found in claw condition, keel bone deviation, and plumage hygiene (P e.001), and there was an interaction effect between housing and hybrid for claws (Pc.Ol), plumage condition (P c.02), and plumage hygiene (P c.os) At 55 wk there were signifcant effects of housing on condition of plumage, bumble foot, foot hygiene, keel bone deviation (P c.ool), and hyperkeratosis (P c.ol), and a significant effect of genotype on claws and foot and plumage hygiene (P c.ol). Again there was a significant housing x hybrid interaction on plumage condition (P c.ool). Very poor plumage condition in LB as a result of feather pecking in both large-group floor systems at both scorings caused the strong interaction effects between housing and genotype. Thus, the LB hen showed very clearly that it was not coping with this stress, as is also reflected in the dramatic mortality figures. While the LSL hens showed rather similar plumage condition in all three housing systems, the LB in cages had the best plumage condition in all treatments in both hybrids. Hence, perhaps unexpectedly in this sense, the traditional floor system with its lower stocking density per unit of ground floor area did not have a positive effect compared with the more densely stocked aviary system. This may reflect that the stocking density calculated on the available area per hen does not differ very much between the two floor systems because the aviaries provide a lot of space in the third dimension. Although LSL birds in all three housing systems had similar scores for feather condi-

TAUSON et al. Research Report 157 HYBRID LSL LB HOUSING T M C T M C STATISIICAL, SIGNIFICANCE, P< Housing Hybrid Housing X I Hybrid Keel bone denation 355 3.16 3.89 3.35 3.21 3.81,001.43 56 Skinwounds, rearbody 3.75 3.90 4.00 3.95 3.88 4.00.16.37.37 Slun wounds, comb 3.98 3.90 3.93 3.98 3.98 4.00.74.23.69 tion, there were differences in the appearance of feathers for birds in floor systems and those in cages. Birds in the floor systems had large areas of naked skin, but the remaining feathers were still of rather good quality. Buds in the cages, conversely, had retained most of their plumage, but most of the feathers were not smooth and intact in quality. In agreement with other studies reporting on health in both aviaries and cages [6, 81, foot condition and keel bone condition [28] in layers are clearly affected by housing system. Thus, the incidence of bumble foot syndrome and keel bone deviation were problems registered in the floor systems but not in cages (P <.OOl), whereas for hyperkeratosis the opposite was true (P < -01 at 55 wk). The interaction effects on claw length between housing system and genotype were explained by shorter and less excessive growth of claws in LB than inlsl. The greater amount of natural wear from scratching in the litter thus had less effect on the brown hybrid. Regarding the hygienic properties of the housing systems studied, and due to the contact with manurefitter, the feet of both genotypes were much cleaner in the cages.than in either litter system, and there were no significant differences between the traditional system and the aviary. Similarly, but probably due to the effect of perches and the possibility of droppings falling onto birds in such systems, plumage hygiene in the cages was superior at 35 wk. The fact that the LB birds were found to be "cleaner" than the LSL may be largely explained by the fact that traces of defecation are more difficult to detect on brown birds' plumage than on white hybrids. In practice, the perches in a traditional system are commonly fixed on the slats and not elevated so as to facilitate the movement of birds over the slats. However, while birds often prefer to perch in

158 HOUSING AND HEALTH an elevated position, the perches in the present system were installed in this way. Also, the feed troughs in T had perches installed above the middle of them in order to protect them from droppings made by birds walktng in or sitting on them. The arrangement of elevated perches on the slats does not appear to have had any negative effect on plumage hygiene. The most common findings at the autopsy in rank order of total flock averages were salpingitis (8.9% of hens housed), pecking wounds (4.0%), keel bone deviations (2.9%), and hepatitis (1.0%). It was noted that pecking wounds were far more common in the LB buds in the floor systems, but in the cages the LSL showed a higher incidence of wounds. The same observations were made regarding salpingitis and hepatitis in the floor systems. Staphylococci bacteria were often found in the infected organs, indicating that bacterial infection following pecking wounds on the naked skin and around the cloaca are most likely to have caused the infections in various organs. This conclusion also agrees well with results reported by Abrahamsson and Tauson [6]. Because keel bone deviation is caused by long-term pressure against a roost, the heavier LB birds probably showed a higher incidence than LSL of keel bone deviation in both the traditional floor system (5.0% and 0.9%) and in the aviary model (6.1% and 1.2%). Keel bone deviations in the caged birds averaged less than 0.5% of hens housed. The results of TI duration revealed no significant differences between housing or hybrids. This is in contrast to reports by Jones and Faure [Z] and Hansen et al. [29], who found that birds in cages had longer duration of tonic immobility than buds in pens, indicating that caged birds are more fearful. However, the latter authors found this difference at 70 wk of age but not at 30 wk. LB needed more inductions than LSL (P c.ool) to obtain tonic immobfity, indicating that LB were less affected by such restraining procedures. CONCLUSIONS AND APPLICATIONS 1. This study did not support the theory that non-beak-trimmed medium-heavy brown layers are better adapted to larger flock systems of the traditional design, i.e, a one-tiered floor system as opposed to a multi-tiered aviary system. In both these housing systems the LB hybrid may show similar and comprehensive problems with feather pecking as well as pecking, affecting both mortality rates and production. In cages, this genotype performs well and similarly to the light white LSL hybrid but displays better plumage condition. The latter, in turn, seems well adapted to both cages and large-group systems. 2. When a suitable hybrid, e.g., the LSL, is used, the traditional floor system may yield improved egg quality compared with both cages and aviaries. 3. When birds are reared in a two-tiered system, which allows vertical movement, LSL hens show no difference in proportion of misplaced eggs between a traditional system and an aviary system. The LB hens still lay more eggs outside the nests in the aviary. 4. There is little difference in condition of birds in an aviary and a traditional floor system. Compared to caged birds, both show more defects like keel bone deviation, bumble foot syndrome, and poorer hygiene of feet, but less hyperkeratosis. 5. Tonic immobility seems to be more affected by genotype than by housing condition. 1. Duncan, I.J.H., 1992. Designin environments for animals - not for public perceptions. br. Vet. J. 148:47S- 477. 2. Tan- T. and J.F. Hurnik, 1992. Comparison of behavior and performance of layin$ hens housed in batteiy cages and an aviruy. Poultry &I. 71:235-243. 3. Craig, J.V. and J.C. Swanson, 1994. Review. Welfare ers ctives on hens kept for egg production. Poultly8i. 7Gz1-9~. REFERENCES AND NOTES 4. European Commission, 1997. Report on the Welfare of p g Hens. Scientific Veterinaly Committee Animal elfare Section. Directorate - General for Agrrculture mii. 2. Brussels, Belgium. 5. Farm Animal Welfare Council, 1997. Report on the Welfare of Laying Hens. Farm him. Welfare Council, Surbiton. Surrev. -, Great Britain. 6. Abrahamsson, P. and R Tauson, 1995. Avialy systems and conventional cages for laying hens. Effects on

TAUSON et al. Research Report 159 production, egg quality, health and bird location in three hybrids. Acta Agric. Scand. 45:191-203. 7. Mhrtensson, L, 1995. Concentrations of Dust, Endotoxin, and 0 nic Acids in Confined Animal Buildings. Dissertationyeport 103. JBT, SLU, Lund, Sweden. 8. Abrphamsson, P., R Tauson, and K. Elwinger, 1996. Effects on production, health, and e& quality of valying proportions of wheat and barley in diets for two hybrids of laying hens ke t in different housing systems. Acta Agric. Scand. 46:17g182. 9. Groot Koerkamp, P.W.G., 1998. Ammonia EG,t%geningen, the Netherlands. 10. Hughes, EO. and MJ. Gentle, 1995. Beak trimming of poultry: Its implications for welfare. World s Poultry Sci. J. 515141. 11. Gentle, M.J., B.O. Hughes, A. Fox, and D. Waddington, 1997. Behavioural and anatomical consequences of two beak trimming methods in 1- and lodayold domestic chicks. Br. Poultry Sci. 38453463. 12. Hunton, P.,1998. The beak trimming controversy. World Poultry 14(2):42-43. 13. Blokhuis, HJ. and J.H.M. Me@ 1995. Aviary Housing for Laying Hens. ID-DLO, Lelystad, the Netherlands. 14. Van Horne, P.L.M., 1996. Production and economic results of commercial flocks with white layers in aviaq systems and battery cages. Br. Poultry Sci. 37:255-261. 15. Kathle, J. and N. Kolstad, 1996. Non-beaked laying hens housed in aviaries. I Production rformance in cages and three types of aviaries. NJAS lk1-24. 16. Abrahamsson, P. and R Tauson, 1998. Performance and egg quality of laying hens in an aviary tem overfivebatchesofbirds. J. Appl.PoultryRes. 72g232. 17. Abrahamsson, P., 0. Fossum, and R Tauson, 1998. Health of laying hens in an aviary system over five batches of birds. Acta Vet. Sand. 39367-379. 18. Craig, J.V. and W.M. Muir, 1996. Group selection for adaptation to multiple-hen cages: Beak-related mortality, feathering, and body weight responses. Poultry Sci. 75294-302. 19. Kjaer, J.B., and P. Srensen, 1997. Feather Fking behaviour in White Leghorns, a genetic study. Br. oultry Sci. W333-341. 20. Wahlstriim, A, R Tauson, and K. E-er, 1998. Effects on plumage condition, health, and mortality of dietary oats/wheat ratios to three hybrids of laying hens in different housing systems. Acta Agric. Scand. 48:25&259. 21. Tauson, R, T. Ambrosen, and K. Elwinger, 1%. Evaluation of procedures for scoring of plumage condition. Acta Agrrc. Scand. 34:400-408. 22. Jones, RB. and J.M Faurc, 1981.Tonic immobility ( righting time ) in layin hens housed in cages and pens. Appl. Anim. Ethol. 736b372. 23. Jones, RB., D.G. Satterlee, J. Moreau, and D. W-n, 1996. Vitamin C supplementation and fearreduction in Japanese quail: Short-term cumulative effects. Br. Poultry Sci. 3733-42. 24. SAS Inslitote, Inc, 1989. SAWSTAT User s Guide. Version 6.4th Edition. Volume 2. SAS Institute, he., Cary, NC. In the statistical model hybrid and housing system were considered fiued. For exterior egg quality traits the weighted means for the registration periods were used. 25. Snedecor, G.W. and W.G. Cochran, 1968. Statistical Methods. 6th Edition. The Iowa State Univ. Press, Ames, IA. 26. Tauson, R and S.A. Svensson, 1980. Influence of pluma e condition on the hens feed requirements. Swedish J! Agric. Res. 1035-39. 27. PegnrL A. and C. Coon, 1993. Effect of feather coverage and temperature on layer performance. Poultry Sci. 72:1318-1329. 28. Tauson, R and P. Abrahamsson, 1994. Foot and skeletal disorders in laying hens. Effects of perch design, hybrid, housing system, and stocking density. Acta Agric. Scand. 41:11&119. 29. Hansen, I., B.O. Braastad, J. Storbrhten, and M. Tofastrud, 1993. Differences in fearfulness indicated by tonic immobili between laying hens in aviaries and in cages. him. Zlfare 2105-112. ACKNOWLEDGEMENTS This study was made possible through sponsorshi b the Swedish Board of Agnculture and the Swedisf: &men Foundation for Agricultural Research. Both organizations are gratefully acknowledged. We also wish to thank the National Veterinaly Institute, Uppsala, Sweden, for carrying out the autopsy of birds and the companies of Agrinova Poultry AB, Uppsala, Sweden and Fienhage, Lutten, Germany for providing the installations of the traditional floor system.