Determining minimal space requirements of group-housed rabbits based
on their spatial distribution
E. van Poucke1, L. Maertens1, A. van Nuffel1, J. van den Abeele2, L.
Lens2 and F. Tuyttens1
1Agricultural Research Centre, Merelbeke, Belgium
2Department of Biology,University of Ghent, Ghent, Belgium
Commercial housing of fattening rabbits (small groups in small barren
wire net cages) constrains the performance of natural behavior and causes
severe animal welfare problems. To increase the absolute space available
per animal without reducing the stocking density, rabbits could be housed
in larger groups. The increased risk of aggression and mortality might
be minimized by adjusting pens according to the animals needs. To
assess the spatial requirements of group housed animals, a new method,
based on the critical interindividual distance, was tested.
It hypothesizes animals to distribute homogeneous if the allocated space
is too restrictive and heterogeneous if it is not. 14 groups of 22 weaned
rabbits housed in pens of 7 sizes (range: 1.32 - 3.27 m²), were studied
during the fattening period. To evaluate the effect of environmental enrichment,
each pen size was provided in a barren and an enriched (2 erect wooden
boards placed next to each other in the centre of the pen) form. Digital
photographs were made every 30 min during 48 hours per pen per week. The
spatial distribution of the rabbits in the pens was determined by dividing
each pen in 4 imaginary identical parts. The number of animals in each
part was recorded. A heterogeneity index, based on the standard deviation
of this numbers, was calculated. This index increased with pen size (p=0.003)
and the presence of enrichment (p<0.0001). Rabbit age negatively affected
the index (p<0.0001) but this effect decreased with pen size (p<0.0001)
and the absence of enrichment (p=0.004). These results suggest that when
housing rabbits in groups, the larger the pen the better, but smaller
pen size may be compensated by enrichment. The developed distribution
method seems efficient for determining the minimal space requirements
of group-housed animals but ought to be validated further. Possible validation
methods will be discussed.
Paper presented
at Measuring Behavior 2005
, 5th International Conference on Methods and Techniques
in Behavioral Research, 30 August - 2 September 2005, Wageningen, The
Netherlands.
© 2005 Noldus
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