In the wild, cover is used by animals to seek shelter from the elements, pr
otection from predators and aggressive conspecifics and as a way to reduce
inter-animal communication. Rearing environments for captive raised fowl of
ten contain open areas that are lacking in complexity and that are greatly
underused. As a result, use of space within pen-type enclosures is often no
t uniform. This paper investigates the effect of increased environmental co
mplexity on the use of space by broilers. The experiment consisted of three
cover treatments (mesh panels, frame panels and no cover) and three group
sizes (80, 110 and 140). The vertical panels, constructed of PVC piping, we
re positioned in pen centers, while the pen centers in the no cover treatme
nt were left empty. It was hypothesized that the provision of vertical pane
ls to pen centers would attract birds into the central space and would lead
to a Inert uniform distribution of birds. Using a grid-coordinate system s
et up in each pen, scan samples were taken on the use of space in each pen
four times per day, 3 days per week from 5 to 44 days of age. Use of space
in the central region for the two cover treatments was significantly higher
than for the no cover treatment (P < 0.0001). The effect of cover treatmen
t on the mean percentage of birds using the central space was influenced by
age (P < 0.0001) and by group size (P < 0.05). Differences in the use of s
pace between the frame and mesh treatment were only found during week 1. In
the side, end and middle regions surrounding the panels, use of space was
influenced by cover treatment and age (P < 0.0001). Over 80% of the use of
pen center occurred at the ends and sides of the panels. These results supp
ort the hypothesis that the presence of vertical panels results in a more u
niform distribution of birds within the pen by increasing the number of bir
ds using the center. (C) 2001 Elsevier Science B.V. All rights reserved.