Effects of feeder space allowance on agonistic behaviour and growth performance of broilers

Oluyinka A Olukosi,  Olajumoke C Daniyan and  Opes Matanmi

Department of Animal Science, Obafemi Awolowo University, Ile Ife, Nigeria
E-mail: oolorunn@oauife.edu.ng

Abstract

One hundred and thirty-two 4-week old unsexed Anak-200 broiler strain chickens were used to study the effect of feeder space allowance on agonistic behaviour and growth performance from weeks 4 to 8. The feeder space allowances (cm/bird) were 2.4, 3.0 and 3.6. The agonistic behaviour that was observed included head pecks, steps, pushes, threats and chase during feeding and “non-feeding” periods.

 Increasing the feeder space reduced agonistic acts (acts/bird/hour) during the feeding period from 7.8 (at 2.4cm feeder space) to 4.5 (at 3.6 cm/bird). There was no effect of feeder space allowance on mean agonistic acts during the non-feeding period. Feeder space allowance had no effect on growth performance parameters. 

Key words: Agonistic behaviour, feeder space, growth performance, broilers

Introduction

The increase in demand for poultry meat and advancement in technology have led to selection of birds to meet these needs. At the same time, the birds are forced to adapt to housing and feeding systems that are largely unnatural to them. It has been argued that in domestication of livestock, economics rather than welfare of the animal is the major consideration (Siegel 1993).

However, an effective management system must take poultry behaviour into consideration, since behaviour is an indicator of welfare (Oluyemi and Roberts 1988). In poultry management, stocking density is an important consideration because of its effect on growth performance of birds. Feeder space allowance is, understandably, a function of stocking density. The effects of feeder space allowance on agonistic behaviour and growth performance of broilers in temperate latitudes have been studied by Anderson and Adams (1992), Cunnigham (1981) and Ouart and Adams (1982). Oluyemi and Roberts (1988) specified that a feeder space allowance of 2.4 cm/bird was sufficient for broilers from 4 – 8 weeks of age.

The effects of feeder space allowance on agonistic interaction in birds raised in a tropical environment are lacking. The general paucity of information on the application of poultry behaviour to poultry management in the tropics was the reason for undertaking this study, which focused on the effects of feeder space allowance on agonistic behaviour and growth performance of broilers.

Materials and methods

One hundred and thirty-two day-old unsexed ANAK-2000 broiler strain chickens procured from a commercial hatchery were used for this study. They were randomly allotted to three treatments, which were feeder space allowances of 2.4, 3.0 and 3.6 cm/bird. There were two  replicates of 22 birds on each treatment. The flight feathers on one wing of the birds were cut to prevent them from flying over to the other replicate. Water was supplied ad libitum in plastic fountain drinkers. A  commercial broiler starter was used from weeks 1-6, while broiler finisher was used from weeks 6-10. The feed was supplied daily at approximately 0630 h (GMT).

The house had solid floors and sides closed in the lower part but open in the upper part for cross ventilation. The average ambient temperature during the period was 38 º C, but about 2 degrees higher in the afternoons. Temperature was read from a thermometer placed inside the house. The commercial feed (purchased from a local feed miller) used was the broiler feed. 

Agonistic behaviour

Observations on agonistic behaviour and growth performance were made at 3-day intervals, starting at week 4 and continuing through week 8. On the days when behaviour was recorded, the feed was supplied to each group at the moment of commencing the “feeding” observations, which began at 0630 h (GMT) and lasted for 10 minutes. Thus a total of one hour was spent observing the six groups. In the afternoon (1400 h GMT) the birds were observed for agonistic interaction during the “non-feeding” period. For this observation, the  door was closed when the observer entered and the birds were given a five-minute adjustment period to adjust to the presence of the observer. Two replicates of each group were observed simultaneously for 15 minutes. 

Agonistic behaviour was defined as head pecking, steps, pushes, threats and chases following the procedures defined by Stone et al (1984) and O’Keefe et al (1988).

Growth and feed conversion

The birds were weighed weekly. Feed consumption was recorded daily.

Statistical analysis

Data on the effect of feeder space allowance on behaviour and on growth performance parameters measured were analyzed using analysis of variance as outlined by Snedecor and Cochran (1967). The effect of the time of day on agonistic behaviour was compared using the “t-test”. Means that were statistically different were separated by Duncan’s multiple range test for a significance level of P£0.05.

Results

 As feeder space was increased, there was a decrease (P<0.05) in the  mean agonistic acts/bird/hour during the “feeding”period, but no effect during the non-feeding period (Table 1). At the two lowest feeder space allowances, agonistic acts were more frequent during the “feeding” compared with the “non-feeding” period. 

Steps and pushes made up more than 90% of the total acts committed (Table 2). Chases were very rarely observed, and were not recorded at all for the highest feeder space allowance.

 Feeder space allowance had no effect on growth performance parameters (Table 3).

Discussion

The effects of decreasing feeder space allowance in increasing agonistic behaviour agree with the findings of Cunningham (1981). This author reported that agonistic acts were highest when the birds were feeding and that with a greater feeder space allowance the birds initiated fewer numbers of aggressive head pecks per hour than when the feeder space allowance was smaller. He suggested that this must have resulted from less competition for feed when the feeding space was sufficiently large.

The greater incidence of steps and pushes compared with threats and head pecks is also interpreted as a response to competition for available feeder space. Usually, smaller birds and those with weak legs were supplanted. Evidently, the birds were more interested in feeding than in threatening other birds.

The lack of effect of feeder space allowance on agonistic acts during the “non-feeding” period is attributed to the decreased tension when the birds not competing for feed. At this time most of them were engaged in “comfort” behaviour as described by Mauldin (1992).

The finding that feeder space allowance did not influence growth performance parameters is in contrast with the report by Ouarts and Adams (1982) that bodyweight gain was reduced by decreased feeder space allowance. This difference may have been due to the housing system, as in the present study the birds were raised on floor, whereas those used by Ouart and Adams (1982) were raised in cages. More plausibly, the reason could have been the greater increment in feeder space allowance in the Ouarts and Adams (1982) study which was 10.2 cm/bird  in contrast to 0.6 cm used in this study.
 

Conclusions 

It is concluded that a feeder space allowance of 2.4cm/bird is adequate for birds raised in a tropical environment.  Although it led to more agonistic acts, it did not adversely affect  growth performance parameters.

Acknowledgements

The authors wish to acknowledge the support of Obafemi Awolowo University, Ile Ife in funding this research.

References

Anderson  K E and Adams A W 1992  Effects of rearing density and feeder and water spaces on the productivity and fearful behaviour of layers. Poultry  Science 71: 53-58

Cunningham  D L 1981 The effects of social rank and cage shape on selected behavioural and  performance traits of White Leghorn layers. Poultry Science 60: 2593-2598.

Mauldin  J M 1992 Applications of behaviour to poultry management. Poultry Science 71:  634-642.

O’Keefe  T R, Graves  A B and  Siegel  H S 1988 Social organization in caged layers: the peck order revisited.  Poultry Science 67: 1008-1014.

Oluyemi  J and Roberts  F A 1988 Poultry production in warm wet climates. Macmillan Publishers Ltd., London and Basingstoke, pp. 82-91.

Ouart  M D and Adams  A W 1982 Effects of cage design and bird density on lay 2. bird movement  and feeding behaviour. Poultry Science 61:  1614-1620.

Siegel  P B 1993  Behaviour-genetic analysis and poultry. Poultry Science 72: 1-6.

Snedecor  G M and  Cochran  W G 1967  Statistical methods. Iowa State University Press, Ames, Iowa. pp. 299-388.

Stone  N N, Siegel  P B, Ackinsson  C S and  Gross  W N B 1984 Vocalization and behaviour of two commercial stocks of chicken.  Poultry Science 51: 1928-1937. 

Received 1 Sept 2000

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