The results showed that the reduction in body weight at higher group sizes was not associated with increased inter-individual variability in body weight. Time at the feeder was similar across group size and the level of agonistic interactions was very low throughout the rearing period. The frequency of fights was not affected by group size. However, the frequency of threats decreased with increasing group size. These results suggest that reduced growth at higher group sizes was not a consequence of restriction of access to resources or other social factors in broiler chickens. Alternative explanations should be considered to explain this effect in broiler chickens.

The level of general activity and the frequency of different patterns of behaviour were similar at all group sizes. However, the higher frequency of disturbances observed at higher group sizes may have contributed to the reduced growth at larger group sizes. Disturbances occurred when chickens tried to obtain a place for resting beside other birds, and they were not motivated by aggression.

            
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