AN AUSTRALIAN first study has revealed free range chickens spend more time outside when there are fewer hens per hectare and greater outside space available.
The research was done by the University of New England and CSIRO in conjunction with the Poultry Co-operative Research Centre.
Dr Dana Campbell, from the School of Environmental and Rural Science, says greater consumer interest in animal welfare is driving change in the laying hen industry in Australia, with an increase in free range farms.
Six small flocks of 150 ISA brown hens were tracked by researchers using radio-frequency identification tracking technology that identified individual hens by their microchipped leg bands.
Each flock had access to one of three different outdoor stocking density areas. The first was 2000 hens per hectare, the second 10,000 hens/ha and the third 20,000 hens/ha.
"What we found is that hens with the lowest outdoor stocking density of 2000 hens per hectare spent more time outdoors, while hens housed at the highest stocking density of 20,000 hens/ha spent the least time outside."
The study also revealed that 2% of tagged hens in each group never ventured outdoors but 67-81% of birds used the range daily.
On average about half of hens were outside simultaneously, using all the available areas of the range.
Free range systems provide hens with a choice between indoor and outdoor areas with the chance to access fresh air, variable weather and exhibit behaviour such as foraging, sun bathing and eating insects.
"The longer time spent in the lowest stocking density may have been partially related to the ground coverage as vegetation did not disappear completely as within the ranges of the other two densities. Previous observations in free range systems showed hens spent more time walking and foraging on grass over gravel," Dr Campbell said.
"Hens may use the range more in lower stocking densities but we are now looking into what that means in terms of hen welfare, including the behaviours they exhibit on the range and overall hen health."
Dr Campbell said further research was needed to determine the optimal design of free range environments that improved hen welfare.
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