CORVALLIS, Ore. – A recent study from the Veterinary College at Oregon State University found that planting hedges in pasture-raised chicken farms may reduce heat stress to help certain breeds of chicken grow faster and increase their yield. immune response to better enable them to fight against pathogens.
This, in turn, could improve the profit margins of commercial poultry farms that choose pasture farming as a more humane way of raising chickens for meat.
The study results are also applicable to anyone raising chickens at home, according to the study authors.
âThe aim of the study was mainly to help small producers, people who sell in farmers markets and small farms who do backyard work, but I think it could definitely benefit people. who are just amateurs, âsaid Marissa Pollak, one of the authors of the paper, published in Frontiers in Animal Science, and a fourth year student at Carlson College of Veterinary Medicine at OSU.
Co-authors include Holly Rysenga, fourth year veterinary student, Eilea Delgadillo and Caroline Glidden, recent OSU graduates, Assistant Professor Brianna Beechler and Professor Anna Jolles.
The study, conducted in the summer of 2019, looked at two breeds of chicken popular among commercial broiler producers, the Cornish cross and the Red rangers. The researchers bought 80 chicks of each type and separated them into experimental and control groups, so that half of each breed lived with access to a pasture with a hedge and half without a hedge.
The researchers followed two main factors: the growth rate, which was measured by weekly weighings, and the immune response, measured by examining the number of white blood cells from weekly blood samples.
Cornish crosses with access to a hedge showed a modest increase in growth rate, and red rangers showed a slightly improved immune response, compared to chickens that did not have access to a hedge.
The researchers hypothesized that the improvement in week-to-week weight gain was due to the decrease in heat stress, as Cornish crosses with access to the hedge received additional shade. The increase in weight gain occurred without an associated increase in food intake in this group. Cornish crosses are popular among commercial breeders due to their faster growth rate, but they are not good foragers and tend to be more vulnerable to outdoor conditions.
There were several very hot days in the summer of 2019, and on those days, Pollak said many chickens without access to the hedge were spending more time inside the coop to get relief from the sun, as the open pasture had no other source of shade.
Red rangers with access to a hedge did not show an increase in weight gain, but did show a slightly increased immune response in the bacteria elimination test conducted by the researchers every week.
âWe speculated that this was because they ate and fed on a variety of insects and plant material in the hedge,â Pollak said. Unlike Cornish crosses, the researchers noted, red rangers are good for foraging outdoors.
A stronger immune response is important for pasture-raised chickens because of the challenge of maintaining hygiene, Pollak said. Farmers cannot completely decontaminate outdoor barns and pastures due to porous materials, so it is difficult to eliminate pathogens such as salmonella after a flock has been exposed.
While the improvements in the hedge groups were statistically significant, the results weren’t “day and night,” Pollak said.
âBut we’ve seen overall improvements with the hedges, so I would always recommend that if the farmers have the capacity, they put them with their chickens,â she said. âThis study contributes to a body of knowledge that ideally should be much larger. There is much more that could be done to help people raise pasture chickens.