Applied Animal Ethology, 9 (1982/83) 341-349 341 Elsevier Scientific Publishing Company, Amsterdam - Printed in The Netherlands

SOCIAL AND SPATIAL ORGANIZATION OF MALE BEHAVIOUR IN MATED DOMESTIC FOWL

P. PAMMENT, F. FOENANDER and G. MCBRIDE

Animal Behaviour Unit, University of Queensland, St. Lucia, Qld. 4067 (Australia)

(Accepted for publication 11 March 1982)

ABSTRACT

Pamment, P., Foenander, F. and McBride, G., 1983. Social and spatial organization of male behaviour in mated domestic fowl. Appl. Anim. Ethel., 9: 341-349.

Observations were made of male spacing, mating and agonistic behaviour in 2 pens of mated domestic fowl. In both pens, site attachment was found, with a bunching of observations for cocks living close to a wall. High-ranking males appeared to move over smaller areas than did low-ranking males. A simple model of dominance relationships between cocks .provided a good explanation of the interferences to mating by threatening neighbours. In the larger pen (3.18 ml/cock), the interference was best explained by a territorial type of model, with the most dominant cocks threatening subordinate males mating close to the range centres of either. In the smaller pen (1.95 ml/cock), the effects of fixed sites were negligible, while the threats by dominant neighbours depended on the distance between the males and the orientation of the mating subordinate towards the dominant. The results emphasise the dynamic nature of social systems and the types of social control operating on interactions.

INTRODUCTION

Site attachment has been observed in domestic fowl houses (McBride and Foenander, 1962; Craig and Guhl, 1969; Tribe, 1980). McBride and Foenan- der suggested that the area moved over reflected the number of hens each bird could remember in stable social relationships. Craig and Guhl (1969) found site attachment in flocks of 200 and 400 hens, and reported that the further a bird moved from the centre of its area, the fewer birds it pecked and the more birds it was pecked by. Thus, pecking pressure appeared to operate as a reinforcer, maintaining each bird within its area of attachment; they also showed a clear social control over interactions due to fixed site effects, and, most importantly, evidence of dynamic processes maintaining stable social structures within flocks. Other evidence of the dynamic nature of individual spacing was provided by McBride et al. (1963), with dominance, spacing and orientation contributing to individual dispersal.

McBride et al. (1969) found a variety of spacing systems in feral fowl, from territorial, through a range of types of social control by dominant

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cocks, to subordinate status. Most showed clear site attachment with over- lapping ranges, but dynamic control of posture and interactions within the vicinity of dominant cocks.

Studies of mated domestic males have not been frequent. Craig and Bhagwat (1974) found that the type of pen affected mating behaviour. In small pens of 2 males and 10 hens, the dominant male did nearly all of the mating, while the subordinate usually hid in corners or retreated to the roosts or nests. They studied mating behaviour only in pens too small for male “territories” to emerge. They showed, however, that hen-hen inter- actions were less frequent in the presence of males; a social control.

It seems that site attachment with spatial defence can occur only when space is adequate; this behaviour is essentially territorial, since birds are dominant over the area and have priority in mating.

This study aims to examine the spatial features of social interactions in 2 pens of mated domestic fowl.

, / X

Pen A. 7,3m. x 6.lm

X

Pen B. 6.11-n. x &Em.

Fig. 1. Layout of Pens A and B, showing size and location of feeders, drinkers, roosts and nests.

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MATERIALS AND METHODS

Observations were made in 2 pens of Australorp fowl, mated for the production of commercial hatching eggs. The shape and dimensions of the pens are shown in Fig. 1; the areas are A = 44.53 m2 and B = 29.28 m2. Pen A contained 14 males and 247 hens, and B had 15 cocks and 164 hens; all males and 48 hens in each pen were tagged for individual identification. The pens were furnished similarly, with roosts, tube feeders, nest boxes and outside wall troughs for water.

Observations

The pens were observed from 05.30 to 09.30 h and 16.00 to 19.00 h from mid-winter to early summer. Mimeographed plans were used to record the positions of individual birds and of interactions; there were enough “landmarks” to allow accurate plotting.

The data recorded were as follows: (i) the position of any mating, the identity and head orientation of the

male (M) and his nearest male neighbour (NN), together with whether NN threatened M;

(ii) the position and identities of any 2 males engaged in agonistic en- counter, along with the dominance outcome;

(iii) at other times, the position and identity of any cock or hen whose tag was visible was recorded.

Observations were made by an experienced observer sitting on a step- ladder about 2 m from the pen; the whole pen was visible.

RESULTS

Peckorder

The matrices of outcomes of dominance interactions were converted into linear hierarchies.

Spatial distributions

The X (longer side) and Y coordinates (in metres) of each bird-position were summarized for each cock. From these data, the variance between males was analysed and the means, standard deviations, skew in relation to the closest wall along that axis, and kurtosis were calculated for each male. The spatial data for individual males are shown in Table I.

It can be seen that there is a significant difference between cocks for each dimension of each pen, though only means at the opposite ends of the pen-dimensions differed significantly. Thus, there are differences in the areas of movement of males and thus presumably site attachment, but these

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TABLE I

Mean position (m). standard deviation, skew in relation to closest wall along axis, and kurtosis for ranked males in Pens A and B. Results of analysis of variance between mean positions, and tests of significant skews and kurtosis are also shown

Rank Mean (m) Std. dev. (hi=l)

X Y X Y

Pen A (7.3 m X 6.1 m)

1 2.93 2.11 2.01 1.27 2 2.82 1.47 a 1.38 1.03 3 3.47 2.14 1.62 1.36 4 3.62 2.30 2.08 1.43 5 3.45 1.70 a 1.32 1.41 6 1.99 a 2.98 1.37 1.71 I 4.27 b 2.04 1.68 1.49 8 3.93 3.35 b 2.11 1.80 9 2.84 2.10 1.88 1.80

10 3.02 2.62 1.42 1.49 11 3.51 2.01 2.10 1.18 12 2.95 3.23 b 1.81 1.10 13 3.27 2.52 2.02 1.52 14 3.59 3.64 b 1.74 1.69 Mean X analysis: F (13.248) = 1.78: P<O.O5 Mean Y analysis: F (13,248) = 3.37: P<O.OOl

Pen B (6.1 m X 4.8 m)

1 2.75 2.04 1.52 1.02 2 3.16 1.79 a 1.89 1.25 3 3.55 b 1.71 a 1.88 1.25 4 2.83 2.79 b 1.39 1.41 5 2.19 a 2.21 1.50 1.21 6 3.21 1.72 a 1.70 1.07 7 2.92 2.43 1.49 1.21 8 2.84 2.38 1.55 1.42 9 3.37 1.90 1.58 1.07

10 2.26 a 1.93 1.57 1.29 11 2.56 2.14 1.59 1.24 12 3.12 2.51 1.71 1.14 13 2.74 2.23 1.57 1.21 14 2.91 2.22 1.64 1.32 15 3.25 2.49 1.43 1.27 Mean X analysis F (14.398) = 2.29:P<O.O05 Mean Y analysis F (14,398) = 2.51; P<O.O02

Skew Kwtosis

X Y X Y

0.70 0.91 t -0.44 1.00 1.14 t 0.96 0.64 0.98

-0.17 0.98 t -1.22 0.52 -0.04 0.81 t -1.41 -0.15 -0.24 1.56 t -1.04 2.36 t 1.29 t 0.50 1.66 -1.22 0.67 1.40 t -0.45 1.33 0.05 -0.56 -1.58 -1.53 0.68 0.41 -1.05 -1.14 0.86 0.23 -1.04 -1.50 0.16 0.67 -1.46 -0.33 0.75 -0.14 -0.45 -1.30 0.36 0.40 -1.34 -0.82 0.00 0.53 -0.32 -1.42

0.27 1.03 t 0.05 1.07 t 0.57 1.27 t

-0.21 -0.01 0.78 t 0.13 0.08 0.95 t 0.13 -0.13

-0.12 0.40 -0.06 0.49 0.65 t 0.50

-0.03 0.43 0.25 0.17

-0.04 0.62 t 0.36 0.34 0.28 -0.14

-1.31 t 0.82 -1.61 t 0.61 -1.05 0.62 -0.63 -1.08 -0.23 -0.63 -1.21 0.88 -0.90 -0.82 -1.33 t -1.17 -1.20 t -0.57 -0.58 -1.00 -1.19 t -0.48 -1.12 -0.47 -1.10 -0.55 -1.11 t -0.82 -1.23 -0.89

Means marked “a" are significantly different from “b". P<O.O5. t : Skew or kutosis t test, P<O.O5.

areas are widely overlapping. Most means are close to the pen centres, al- though significant skews and kurtosis suggest that means are not always

good indicators of the centres of the areas to which males may be attached. Modes may be a better measure of location; but the number of observations per bird varied considerably, with some birds having few records. Medians were calculated, but these did not differ appreciably from the means. In the Y coordinates, the skews became positive and significant as the means ap- proached the long walls; these were presumably edge effects and the positive

correlations between skews and kurtosis (X, 0.68, P-CO.01; Y, 0.86, EO.01)

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emphasised this bunching of observations when birds lived along walls. There was no relationship between the axes. Rank also correlates significantly with the skew Y (-0.51, P<O.Ol) and kurtosis Y (-0.61, P<O.Ol), but careful observation of the data suggests that this is misleading. In fact, the alpha male is close to the centre of the group but there is no clear arrangement of the other birds in space.

Mating interactions

The data collected is the male’s number (M), his nearest neighbour (NN), their positions and orientations, and whether the NN threatened M or not. Table II shows the frequency of each cock’s matings, and frequency of being a nearest neighbour with and without threats.

A discriminant function analysis was used to examine some of the factors which may contribute to the threat-non-threat difference between matings. A model, presented in Fig. 2, was used to represent the spatial variables which may contribute to the dynamic social situations involved in making a mating. If the cock’s home base, or the centre of his area of movement, influences his tendency to mate or intrude on another’s mating, then his distance from it may influence his behaviour. Similarly, the distance between

TABLE II

Frequency of matings, threats and no threats when a nearest neighbour for ranked males in both Pens A (14 birds) and B (15 birds)

Bank Pen A Pen B

Matings Nearest neighbour Matings Nearest neighbour

Threat No threat Threat No threat

1 9 2 2 6 2 3 7 7 4 2 1 5 15 0 6 1 0 7 7 0 8 10 3 9 1 0

10 4 2 11 10 1 12 8 0 13 10 0 14 1 0 15 - -

6 17 0 12 1 10 2 11 7 21 4 9

17 10 0 13 2 0 0 4 7 12 5 5 1 7 0 10 1 5 1 6 4 9 6 9 3 11 1 7 7 10 0 14 2 1 0 5 8 3 2 4 7 18 1 10

- 13 0 6

Totals 91 18 73 147 22 125

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k: C ------ NN home

M base

mated here

9

Fig. 2. Model of mating spatial variables relating inter-distances of maters (M) position, nearest neighbour (NN) position, and their home bases; together with M and NN head angles to each other at mating.

the home bases of neighbours may contribute to their social relationships and thus their tendency to interact competitively or agonistically. Spatial factors, other than those concerned with fixed sites, are the distance between the males and their orientation relative to each other at the time of the mating. Non-spatial factors included the rank of each male and the total number of interactions which were observed between each pair of birds, for this reflects the dynamics of their relationship and is different for each pair of cocks. In this way it differs from peck-order, since this only con- siders the winner, or relative winner, in all relationships.

The 11 variables were used as predictors in the discriminant function analyses of the 2 groups, threat or non-threat by NN at mating by M. Table III shows the variables and their respective correlations with the discriminant function, together with group means, and indicates if the association univari- ate F test was significant.

The analysis was done for each pen and repeated, using medians instead of means, for the X and Y coordinates of home bases. The results were identical for both pens, so that only the results using the means are presented.

The multivariate F and x2 tests for Pens A and B are significant at 4.5% and 0.05%, respectively. Thus, the function for B is much more stable and accounts for more of the variance than for Pen A. The ranks of M and NN are consistent in their contribution to the discrimination. Typically, NN threatened M when it held a higher rank than M. In Pen A, the threats were typically from high- to middle-ranking cocks (mean ranks 4.7 and 9.0) while in Pen B they were from middle- to low-ranking cocks (7.2 and 11.7). There were no threats when M had a higher rank than NN (mean ranks 6.8 and 7.3, respectively, and in Pen B, 6.7 and 7.4). The interaction frequency in the relationship between M and NN had no important effect in either pen.

Among the spatial variables, the picture differed in the 2 pens. Fixed site variables seemed more important in Pen A, while individual spacing and orientation were more important in Pen B. In Pen A, shorter distances be- tween NN and its own and M’s base contributed to threats, while in Pen B the distance between M and NN was half as great with threats as without

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TABLE III

Results of the discriminant function analysis between threat and non-threat groups in mating for Pens A and B. The significance of the function for each pen is shown. The correlations of the variables with the function, together with group means and univariate F tests, are also shown

Variable Pen A Pen B 18 threat group 22 threat group 73 no threat 125 no threat h = 0.79 A = 0.78 Multiv. F (11,79) = 1.96; P<O.O4 Multiv. F (11,135) = 3.47; x2 (11) = 20.36; P<O.O4 P<O.OOl

x* (11) = 34.99; FYo.001 -____ -

Carrel. Group means Correl. Group means ___... __._- - Threat No threat Threat No threat

Rank M -0.46 9.00 Rank NN 0.52 4.72 Interactions -0.07 3.56 M to base 0.37 2.26 NN to M-base 0.45 2.14 M to NN-base 0.42 2.30 NN to base 0.58 2.02 M to NN -0.10 0.74 Base to base 0.22 0.97 M angle to NN 0.36 30.86 NN angle to M -0.17 109.92

6.85* -0.78 7.29** 0.04 3.32 -0.19 2.68 0.19 2.70* 0.18 2.83 -0.03 2.80** -0.02 0.68 0.45 1.09 0.00

53.72 0.43 99.65 -0.14

11.72 6.74** 7.18 7.42 3.86 3.16 1.94 2.17 1.87 2.07 2.10 2.07 2.00 1.98 0.52 0.92** 0.68 0.68

24.25 54.07** 105.38 94.37

Significance of univariate F tests: ** at 1%; * at 5%.

threats (0.52 vs. 0.92 m). Similarly, threats occurred when M was almost facing its dominant neighbour (24” mean) compared with 54” when no threat followed.

DISCUSSION

The flocks studied were necessarily small and the distribution of facilities meant that the birds needed to move over most of the pents to complete a daily cycle of activities. Nevertheless, there was some site attachment in both pens. The skew data suggested edge effects in movement patterns of males whose areas of movement overlapped but differed significantly. A significant correlation between rank and kurtosis (-0.61, X0.01) suggested that the suggestion of Guhl (1953) that dominant birds may have greater freedom of movement is not borne out; indeed, they seem to use less of the pen than do their subordinates.

The mode or median coordinate values may give a better picture of the

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birds’ range centre than does the mean; the means were used throughout the study because modes were not practical and the medians were very similar to the means, probably because of the relatively large grids used to transcribe the data from floor plans. Larger and better data may be nec- essary to give reliable modes or medians.

The social structure and interaction dynamics were clearly different in the two pens (A = 14 cocks:247 hens; B = 15 cocks:164 hens). In Pen A, subordinate birds were likely to be threatened by dominant neighbours near to their own and the mater’s range centres, probably in the area between the 2 centres. Certainly the location in relation to fixed sites in the pen was affecting interference at mating and the social control activity of dom- inant cocks; site attachment of this type borders on territoriality.

In the smaller Pen B, the site attachment was present but did not appear to contribute strongly to the interference by dominants in the mating ac- tivity of their subordinate neighbours. Instead, the inter-individual distance and orientation of the mater elicited threat behaviour. Social control was thus better explained by a personal sphere of social control than a territorial model. The relative sizes of the 2 pens seems important here. The total densities were similar (0.170 and 0.164 mz for A and B, respectively) but are quite different for the cocks (3.18 and 1.95 m’/cock). Since males and females typically organise themselves separately, socially and spatially, within the same space, the different densities of the cocks in the 2 pens is the most likely explanation of the change from territorial to hierarchical emphasis, a transition observed by Shoemaker (1939).

The simplistic linear hierarchy model gave a clear picture of the organisa- tion of interference at mating in both pens, while the quality of the relation- ships had no explanatory effects. The linear dominance model has been widely and justifiably criticised for many reasons, yet it has consistently provided a useful picture of the social organisation of small groups, especially of domestic animals.

Perhaps the most useful picture is that of the dynamics of social inter- actions. The dominance models fits the data, but is restricted to proxemic social controls in the small pen with territorial types of constraints in larger pens. Subordinates may mate, but when they ignore the immediate social context the rewards may be painful!

ACKNOWLEDGEMENTS

Thanks are extended to A. Moffatt of Mt. Gravatt. Queensland, for per- mission to study birds in his flock, and to the Poultry Research Advisory Committee of Australia for a grant to carry out the analyses.

REFERENCES

Craig, J.V. and Bhagwat, A.L., 1974. Agonistic and mating behavior of adult chickens modified by social and physical environments. Appl. Anim. Ethol., 1: 57-65.

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Craig, J.V. and Guhl, A.M., 1969. Territorial behaviour and social interactions of pullets kept in large flocks. Poult. Sci., 48: 1622-1628.

Guhl, AM., 1953. Social behaviour of the domestic fowl. Kans. Agric. Exp. Stn. Tech. Bull. 73, 48 pp.

McBride, G. and Foenander, F., 1962. Territorial behaviour in the domestic fowl. Nature (London), 194: 102.

McBride, G., James, J.W. and Shoffer, R.N., 1963. Social forces determining spacing and head orientation in a flock of domestic fowl. Nature (London), 197: 1272-1273.

McBride, G., Parer, L.P. and Foenander, F., 1969. The social organization and behav- iour of the feral domestic fowl. ANim. Behav. Monogr., 2: 127-181.

Shoemaker, H.H., 1939. Social hierarchy in flocks of the canary. Auk, 56: 381-405. Tribe, A., 1980. Environmental design and site attachment in flocks of broiler chickens.

M.Ag.Sc. Thesis, University of Queensland, 194 pp.