1、Dustbathing by broiler chickens: a comparison of preference for four different substrates Sara J. Shields, Joseph P. Garner, Joy A. Mench Department of Animal Science, University of California at Davis, one Shields Avenue, Davis, CA 95616, USA Received 28 February 2003； received in revised form 28 A
2、ugust 2003； accepted 21 January 2004 Abstract Leg abnormalities leading to lameness in broiler chickens are a serious welfare problem. Previouswork in our laboratory demonstrated that providing broiler chickens with the opportunity to exercise byperforming more natural behaviors (such as perching, w
3、alking up and down inclines and dustbathing)can improve their ability to walk normally J.A. Mench, J.P. Garner, C. Falcone, Behavioral activityand its effects on leg problems in broiler chickens, in: H. Oester, C. Wyss (Eds.), Proceedings of theSixth European Symposium on Poultry Welfare, Worlds Pou
4、ltry Science Association, Zollikofen, Switzerland, 2001, pp. 152156. With the long-term goal of stimulating dustbathing to improveleg condition, the aim of this study was to determine the dustbathing substrate preferred by broilerchickens.We conducted a dustbathing choice test experiment using four
5、different bedding types (pinewood shavings, rice hulls, construction grade sand, and a recycled paper animal bedding product).Four different broiler chickens were tested each week for 6 weeks starting when the chicks were1 week old. They were selected from two groups of broiler chickens housed in la
6、rge home pensbedded with wood shavings. Selected birds were tested in smaller pens where they were deprivedof all loose bedding material except during testing, which was carried out for 1 h each day for three consecutive days per week. During an observation, each corner of the test pen was filled wi
7、th adifferent bedding type, and the behavior of the focal chick recorded. Vertical wing shakes (VWS)were used as the primary measure of dustbathing activity. Broilersperformed significantly moreVWSper hour in sand (F3,36 = 13.52,P 0.0005) and spent a greater proportion of their total time in sand(F5
8、,60 = 5.15, P = 0.001) than in the rice hulls, paper, or wood shavings. They also visited the sandsignificantly more often than the paper or the wood shavings (F5,60 = 96.47, P 0.0005). Therewere no dustbaths in the rice hulls. The latency to enter sand was significantly shorter than the latencyto e
9、nter any of the other three substrates (F3,15 = 5.24, P = 0.0113). Ground pecking generallyprecedes a dustbathing bout, and the rate of pecking and the proportion of the total time budget spentpecking were also highest for sand (F3,51 = 24.49, P 0.0001 and F3,51 = 15.28, P 0.0001,respectively). The
10、preference for sand wasapparent in the first week, and was stable with age. Theresults of this study suggest that sand is attractive to broiler chickens and is a potent stimulus for dustbathing. Further work is needed to determine if stimulating broiler chickens to dustbathe by providing sand can im
11、prove their leg condition, and thus their welfare. 2004 Elsevier B.V. All rights reserved.1. Introduction Exercise is essential for the health and well-being of animals. For broiler chickens even walking may be difficult as the birds age due to rapid growth rate and the increasing incidence of leg d
12、isorders (Weeks et al., 2000； Kestin et al., 1992； Mench, 2004). Previous work in ourlaboratory (Mench et al., 2001) and other work (Thorp and Duff, 1988) suggest that exerciseis important for reducing the incidence and severity of leg problems. For broiler chickens,one form of exercise is dustbathi
13、ng behavior. Because dustbathing involves rotational andpushing motions of the legs, it could be a form of exercise that improves leg condition. Layinghens have been found to have clear preferences for dustbathing substrates (Petherick andDuncan, 1989； Vestergaard and Baranyiova, 1996； van Liere, 19
14、91), but the preferencesof broiler chickens have not yet been thoroughly examined, particularly for bedding thatis available on a commercial scale in the US. Our aim was to determine which substrate,out of four commercially available bedding types, was the best for eliciting dustbathing bybroiler ch
15、ickens. A dustbathing bout is composed of a sequence of behavioral components (Kruijt, 1964). Pecking and scratching at a potential dustbathing site usually precede a dustbathing bout. The sequence of dustbathing behavioral components usually begins with “bill-raking”, where the bird, in a sitting p
16、osition, pulls loose substrate closer to its body, constructing a small ridge of loose substrate. Then, while still in a sitting position, the bird performs verticalwing shakes (VWS) during which small particles are tossed upward into the feathers. Oncedirt particles have been collected in the feath
17、ers, the bird lies down on its side and performsside-rubs or head-rubs. Side-rubs involve motion of the legs as the bird pushes its bodywhile in a lying position. When the dustbathing bird is finished with its bath, it stands andconcludes the bout with a ruffle-shake, shaking off loose dirt particle
18、s. The working ofloose substrate like dust or dirt through the feathers is thought to function in absorbing stalelipids in the plumage (van Liere, 1991).Under commercial rearing conditions, broiler chickens may not have access to loose friablesubstrate during the whole growing period because their b
19、edding becomes compressedand dirty with use over time. In this situation, dustbathing may not be elicited to its fullest. Like laying hens, broiler chickens probably also have preferences for particular substrates in which to dustbathe. If the bedding provided is not of a preferred type, it may furt
20、her deterthem from dustbathing.Young and adult laying strain chickens prefer peat to sand, and sand towood-shavings andstraw, for dustbathing (Petherick and Duncan, 1989； Sanotra et al., 1995； van Liere, 1991；Vestergaard and Baranyiova, 1996). However, dustbathing preferences of broiler chickenshave
21、 been examined in only one study. Vestergaard and Sanotra (1999) provided broilerchicks with either sand or straw in which to dustbathe for twenty-six 1 h sessions. Severalof the birds did not dustbathe on every day the substrates were presented, and the numberof days in which dustbathing did not oc
22、cur was almost twice as many for those birds givenstraw than those given sand. This result suggests that, at least for sand and straw, broilerand layer preferences are similar. However, the dustbathing choice tests performed so farusing broiler chickens have not evaluated any of the other substrates
23、 tested for laying hens,or the commercially available bedding types that would be easy to obtain in large quantitiesin the US.Before the effect of dustbathing alone on leg condition can be assessed, the conditions that will elicit the most dustbathing behavior from a broiler chicken need to be deter
24、mined.The present experiment was performed in order to determine which of four bedding types,wood shavings, rice hulls, masonry grade sand, and a recycled paper-bedding product,wouldelicit the most dustbathing behavior in commercial strain broiler chickens. These substrateswere chosen either because
25、 they are already in widespread use in the US, are available ona commercial scale, or are being considered as alternatives to traditional bedding (Grimeset al., 2002).We examined differences in the amount of dustbathing performed, the latencyto perform dustbathing, the latency to enter each substrat
26、e, the amount of time spent in eachsubstrate, the number of visits to each substrate, the length of a dustbathing bout in each substrate, and the amount of pre-dustbathing appetitive pecking behavior performed in eachsubstrate. 2. Methods 2.1. Subjects and housing This study, which was part of a lar
27、ger study of the effects of strain differences on gait, was approved by the University of California, Davis Animal Use and Care Administrative Advisory Committee. Cobb (N = 52) and Ross (N = 52) day-old male broiler chicks were obtained from a commercial hatchery. The birds were marked with colored,
28、 numberedidentification tags. Half of the birds of each strain were placed in one floor pen (measuring3.05m square), and the other half of the birds were placed in an identical adjacent floorpen. Each pen contained wood shavings for bedding and an overhead brooder for heat.There were windows along the length of the building that allowed daylight to enter thepens. Overhead fluorescent lights were on continuously for the first 4 weeks, and were thenadjusted to provide an 8D:16L schedule. Food
