Space use according to the distribution of resources and level of competition

Abstract

The manner in which an animal moves throughout and utilizes the space available to it depends on the dispersal, availability, and level of competition for resources the animal requires for its biological functioning. We tested groups of broilers (Gallus gallus domesticus) in 3 experimental group sizes of 5, 10, and 20 individuals per group under 3 resource distribution patterns. Groups were tested with access to 1 large single feeder, 2 medium-sized feeders, or 4 small feeders. In all arrangements the total amount of food available per bird remained constant. During the first phase groups had free access to all available feeders, and in the second phase access at each feeder was restricted to a single bird. Space use, measured by calculating core areas and interindividual distances between group members, increased as group size grew larger and as feeders became more widely distributed. Not all group sizes responded equally to the resource distribution patterns. Space use patterns for the smaller group sizes were more strongly affected by resource distribution patterns than the larger group sizes. When access to the feeders was restricted, consumption, aggression, and space use increased. Broilers adjusted their space use and aggressive behavior according to the level of competition, dictated not only by group size but also resource distribution and accessibility.