BLACKSBURG, Va. – Fast-growing broiler chickens range more in a silvopasture than a grass pasture, new research finds.

Allowing chickens to range and have access to the outdoors provides positive welfare outcomes for the animals, like reducing anxiety, encouraging natural behaviors such as foraging, and improved gait and footpad health, according to experimental studies. However, birds with free-range access often don’t go outside.

“Pasture access is considered an animal welfare improvement, but the pasture design is often (not) taken into account,” said Leonie Jacobs, associate professor of poultry welfare at the School of Animal Sciences at Virgina Tech. “Silvopasture has the potential to meet the chickens’ needs really well, since they are jungle fowl descendants, and feel especially comfortable in forested habitat, compared to open grass fields that are commonly used as a range in these systems.”

Silvopasture is the practice of integrating trees and forage into a pasture. A variety of trees and shrubs provide natural shelter and cover from predators, help mitigate weather extremes, and allow for a more varied diet. Importantly, research indicates that silvopasture can increase range use and the amount of time that chickens spend outside. However, previous research has focused on slower growing broilers or laying hens, although broiler chicken free-range production in the U.S. almost exclusively uses conventional, white-feathered, and fast-growing broilers, Jacobs said.

Jacobs and her team studied mixed-sex Ross 708 fast-growing broilers across several experiments which aimed to determine the ranging behaviors of birds in silvopasture versus open grassland plots.

“Silvopasture reduced exposure to heat and cold extremes, creating a more stable microclimate than the open pastures did. Live observations consistently showed more birds using silvopasture. But we also used photographs to determine range use, and in (the photographs), range use was underestimated due to limited visibility,” Jacobs said of the study’s results.

The research group found that broilers are likely to go outside in the morning (46 percent on average in open plots versus 57 percent in silvopasture) but their range use is low the rest of the day. On average, data from live observations showed 9  percent of the birds outside in an open pasture and 15 percent in the silvopasture.

Overall, silvopasture did not guarantee constant outdoor use and in both pasture types, range use overall was a bit low, Jacobs added. Still, the group saw that a silvopasture allowed the birds to use the range when it mattered most for them depending on age and temperature. For example, younger birds appeared to value cover and protection early on and were not deterred by cold, while older birds benefitted from shade during warm conditions while staying inside on colder days, Jacobs said.

“Here we mimicked a pasture-raised system more so than a free-range system, but the results can be translated to commercial free-range approaches,” she added. “Having bushes, tall grasses, and/or trees in the range provides a more preferred outdoor space for broilers.”

Access management also impacts how well a range is used by a flock. Allowing birds outside at earlier ages, allowing access to the range even when weather is subpar, allowing early morning and afternoon access, and providing ramps for birds so they can easily walk outside are all approaches that may stimulate birds actually using the range, Jacobs noted.

“Plant trees and bushes near the house so that broilers feel safe when ranging outdoors. These plants could be an additional source of income. Consider fruit trees, Christmas trees, biomass producers like willows, switchgrass (for bedding), even corn,” she said. “Keep in mind that initial setup may be labor and cost intensive, and advice from other farmers would be especially helpful for new silvopasture producers.”

Jacobs stated that all of her research focuses on providing poultry and sometimes other animals with a good life. She said that it is our obligation since we raise these animals for our own benefit.

“All the work in my research group aims to either improve the lives of these animals, while not impacting or even benefiting production, or to find ways to measure animal welfare,” she said.

As such, the group is searching for funding to continue their efforts. Jacobs said the team is looking to delve deeper into strategies to improve range use in free-range broiler systems. If funded, research will focus on how silvopastures impact biosecurity risks like pathogens and avian influenza, food safety and product quality. They are also interested in investigating other strategies to improve range use, such as allowing birds outside at an early age.

Currently, Jacobs said her team is working with a large-scale commercial integrator to determine the benefits of providing broilers with more space indoors, by incorporating platform perches which add about 12 percent of “floor” space to a house and investigating the welfare and productivity impacts in commercial flocks. Jacobs is also looking for master’s and doctoral students to help with a new project investigating biomarkers for animal welfare.