Progress 10/15/01 to 10/31/04
Outputs
The overall goal of the studies conducted under this grant was to use an understanding of broiler behavior to decrease leg problems by stimulating particular types of activity. Specific objectives were to determine the types of activity needed to decrease leg problems; to modify housing appropriately and assess the effects of gait score on musculoskeletal problems, production, and carcass quality; and to evaluate the course of development of leg problems and elucidate the relationship between gait and specific leg problems. We addressed these goals by conducting studies of: 1) dustbathing development, frequency, intensity and the influence of bedding type; 2) the effects of provision of ramps, feeding platforms, and/or perches; 3) the effects of providing an additional free-range area and of using slow-growing strains and/or low-density diets. Analysis of the data from the free-range studies is currently underway. Other results were as follows: 1. The onset of gait
problems occurs at about 3 weeks, after which they progressively worsen in frequency and severity. There is no predictable relationship between the severity of gait impairment and specific types of leg pathology. 2. In a preference test, broilers preferred sand to other dustbathing substrates. When given a choice between sand and wood shavings as bedding in their home pen, they prefer to dustbathe and perform many of their other active behaviors on sand. However there are no differences in the time budgets, or leg condition, of broilers housed only on sand or shavings. Dustbathing intensity decreased in all birds with age, probably because of fatigue associated with increased muscle mass or pain associated with leg problems. 3. Perches, ramps, and/or feeding platforms are used extensively and have a beneficial effect on gait score, although there are no clear trends in terms of decreasing the incidence of specific leg pathologies. However, these environmental modifications have the
potential to significantly decrease leg problems via increasing exercise.
Impacts
Our studies have shown that relatively simple and inexpensive structural changes (e.g. addition of perches) to broiler pens could help to improve walking ability. Lameness in broiler chickens in both an economic and animal welfare issue, so this result is important for the broiler industry.
Publications
- Mench, J. A., J.P. Garner, and C. Falcone. 2001. Behavioral activity and its effects on leg problems in broiler chickens. Pages 152-156, 6th European Symposium on Poultry Welfare. H. Oester, and C. Wyss, C., eds. Zollikofen, Switzerland, World's Poultry Science Association.
- Garner, J.P., Falcone, C., Wakenell, P., Martin, M. and Mench, J.A. 2002. The reliability and validity of a modified gait scoring system and its use in assessing tibial dyschondroplasia in broilers. British Poultry Science 43:355-363.
- Shields, S.J., Garner, J.P. and Mench, J.A. 2004. A comparison of the behavior of broiler chickens raised on two different bedding types. Poultry Science 83, Supplement 1, p 83. Falcone, C., Mench, J.A. and Wakenell. 2004. Can perches and platforms affect the incidence of gait abnormalities in broiler chickens? Poultry Science 83, Supplement 1, p 362.
- Falcone, C., Mench, J.A. and Wakenell, P. 2004. Effect of perches and platforms on lameness in broiler chickens. In Proceedings of the 38th International Congress of the International Society for Applied Ethology, Helsinki, Finland, p. 122.
- Mench, J.A. 2004. Lameness. In: Measuring and Auditing Broiler Welfare, eds. C.A. Weeks and A. Butterworth. CABI, Wallingford, U.K., pp. 3-18.
- Shields, S.J., Garner, J.P., and Mench, J.A. 2004. Effect of sand and wood shavings bedding on the behavior of broiler chickens. In press, Poultry Science.
|
Progress 01/01/03 to 12/31/03
Outputs
The broad goal of this project is to assess the effects of increasing behavioral activity on skeletal disorders, and particularly leg problems, in broiler chickens. Exercise is known to improve bone strength in animals, and thus could decrease the skeletal problems that are seen in broilers as a consequence of their rapid growth. Four experiments were conducted to address this goal, evaluating the effects of increasing dustbathing, perching, and walking behaviors on activity and leg condition. In Experiment 1, broilers were deprived of the opportunity to dustbathe for 24 hours. Dusbathing substrate preferences of 28 broilers reared on the most commonly used bedding material, wood shavings, were then tested in a choice test each week from 1-7 weeks of age. The broilers strongly preferred to dustbathe in sand as compared to wood shavings, a recycled paper product, or rice hulls. This preference was seen at all ages. This suggested that providing sand as a bedding
material could increase activity. In Experiment 2, therefore, 60 broilers were housed in pens that were divided down the middle so that half of the pen could be bedded in wood shavings, and half in the preferred substrate, sand. Activity patterns were monitored from 1-6 weeks of age. As the birds aged, they spent more time on the sand side of the pen and used the sand more than the wood shavings for several active behaviors, including dustbathing, walking, and foraging. This suggested that housing broilers on sand might increase activity sufficiently to decrease leg problems. Therefore, in Experiment 3, 400 broilers were housed in pens bedded only either in sand or wood shavings, and their activity monitored from weeks 1-6 of age. There were no treatment differences in behavior. Thus, although broiler prefer sand for dustbathing and other activities and will use this substrate if it is available, if no choice is provided the behaviors will still be performed at the same frequency on a
less-preferred substrate. Providing sand as bedding is therefore unlikely to increase activity sufficiently to affect leg problems. In Experiment 4, other types of pen configurations were then studied as a means of increasing activity. Fifty-two broilers were housed in either standard pens, or in enriched pens containing perches and platforms that they had to traverse in order to feed. Walking ability, as measured by the latency-to-lie test (LTL), was improved in the birds housed in the enriched pens, although there was no difference in weight gain between the enriched and control birds.
Impacts
Although broilers prefer and are more active on sand bedding, use of this bedding type is unlikely to improve leg problems. Stimulating walking and perching behavior, however, can result in improvements in walking ability with no decrement in performance. These results are of importance to the poultry industry in best providing for the health and welfare of the birds.
Publications
- Shields, S.J., Garner, J.P. and Mench, J.A. 2003. A comparison of broiler chicken behavior on two different bedding types. In Proceedings of the 37th International Congress of the International Society for Applied Ethology, Abano Terme, Italy, p. 235.
- Shields, S.J., Garner, J.P. and Mench, J.A. 2003. Dustbathing by broiler chickens: a comparison of preference for four different substrates. Applied Animal Behaviour Science. In press.
|
Progress 01/01/02 to 12/31/02
Outputs
During the past year we have begun investigations to determine the effects of increasing dustbathing behavior on skeletal problems in broiler chickens. During a dustbathing bout, birds work friable material through their feathers using rotational movements of the legs, so stimulating this behavior could have beneficial effects on leg condition. Anecdotal evidence suggests that broilers dustbathe less than laying hens, and that they also dustbathe less as they grow older. However, whether this is due to lameness, the fact that the litter type used (usually wood shavings) does not stimulate dustbathing behavior or that the quality (friability) of the litter decreases with time, or to some other factor or factors is unknown. We assessed preferences for dustbathing materials in broiler chickens reared on wood shavings from 1-6 wk of age in a preference testing apparatus after they were substrate-deprived for 24 hours. Broilers preferred sand to wood shavings, a recycled
paper product, or rice hulls for dustbathing, although they preferred to forage in the rice hulls. These preferences were seen even in older birds that had no experience of any substrate except wood shavings, suggesting that the preference for sand or a similar fine material for dustbathing is innate. In a second study we raised broilers in pens filled half with sand and half with wood-shavings. The birds preferred the sand side for dustbathing and resting, and were also more active (walking, pecking, ground scratching) on the sand side. Dustbathing did not decrease with age, and together these findings suggest that sand might be a bedding that will stimulate not only dustbathing, but also other activity. We are currently evaluating the effects of sand bedding as compared to wood shavings bedding on the incidence of leg problems.
Impacts
Sand is being investigated by the poultry industry as a potential bedding because it has been shown to have lower microbiological counts than wood-shavings litter, particularly of important potential human pathogens like E. coli. If this bedding does stimulate activity sufficiently to decrease leg problems, use of this bedding would have the potential to improve bird welfare and economics. Even if not used as a bedding, it might be possible to add sand baths to commercial houses, which would be a practical and low-cost method of stimulating activity by the birds.
Publications
- Garner, J.P., Falcone, C., Wakenell, P., Martin, M. and Mench, J.A. (2002). The reliability and validity of a modified gait scoring system and its use in assessing tibial dyschondroplasia in broilers. British Poultry Science 43:355-363.
- Shields, S.J., Mench, J.A. and Garner, J.P. (2002). Dustbathing substrate preference in broiler chickens: implications for animal welfare. In Proceedings of the 36th International Congress of the International Society for Applied Ethology, The Netherlands, p. 65.
|
|