Patch Discrimination as a Function of Handling Time

Short- and long-term movement patterns in complex confined environments in broiler chickens: the effects of distribution of cover panels and food resources

In captivity, the positioning of structural enrichment and food resources influences behavior and space use. The aim of this experiment was to examine the influence of cover panels and the positioning of food resources on the movement and space use of domestic fowl (Gallus gallus domesticus). Eight groups of 45 male chickens were used for this study. Each group was temporarily divided into 2 groups of 20 birds; each group was used to investigate the influence of cover panels and the effects of food resources. In the cover panel treatments, 20 birds were placed in the 10-m(2) testing enclosures that contained one 2-m cover panel in the center, four 0.5-m panels in a zigzag fashion, or had no panels (controls). In the food resource treatments, the position of the feed trays varied, with 1 feed tray in the center; 2 feed trays, one at each edge; or 4 feed trays, one at each corner of the enclosure. Locations of focal birds were collected through instantaneous scan sampling that was recorded as X,Y coordinates. From these X,Y coordinates, we calculated net and total distance moved, mean and maximum step lengths, and angular dispersion of the path of movement. To calculate long-term space use, 3 replications for each of 3 cover panel and food resource treatments were placed in nine 10-m(2) enclosures for 1 wk. Locations of focal birds in each group were collected by ad libitum scan sampling and data were used to calculate core areas by kernel estimates. Mixed model ANOVA was used to determine the effects of the distribution of cover panels and positioning of food resources on movement parameters during the study period, whereas 1-way ANOVA was used for core areas. Surprisingly, our analyses showed that long-term and short-term movement was not affected by changing the location of cover panels or food resources. Only net distance seemed to be affected to a certain degree by the presence of the cover and the distinctive availability of food resources.

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

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.