How tree cover can boost production and lower flock mortality

Providing tree cover on outdoor ranges has been widely embraced by the egg industry in recent years.

Not only has it helped reduce the prevalence of feather pecking, it has also been found to improve bird welfare. But recent research has also demonstrated that tree cover can improve productivity.

The research, which was funded by McDonald’s, examined if there was a correlation between tree cover and the number of second class eggs and bird mortality.

The authors of the study, Andrew Jôret of Noble Foods and Ashleigh Bright of FAI Farms, collected data from a total of 66 free-range Noble flocks – half with more than 20% tree cover and half without tree cover.

Over the life of the flock, the total number of seconds from ranges with tree cover was reduced by approximately 1%, rising to 1.3% from birds over 45 weeks old.

“In the UK, a second class egg is worth approximately one-third of a Class A egg. If tree cover provision results in approximately a 1% decrease in packing station seconds and a 1% decrease in farm seconds, then in a 10,000-bird flock laying 24 dozen eggs per bird, about 4,800 eggs would move to Class A,” the researchers said.

The study attributed the decrease in the number of seconds to a reduction in the levels of stress. “Stress is a significant factor influencing egg shell quality. Birds on ranges with tree cover may be less stressed than those without trees and therefore produce less second-grade eggs. Tree cover is also likely to provide protection from heat stress.”

The study also found mortality was lower in flocks with tree cover, down from about 16% to 12% on the study farms, though the researchers acknowledged that other factors were also at play.

“Mortality obviously represents a significant economic cost to producers,” said Dr Bright. “While the percent mortality data was not statistically significant, it may still have important implications for producers. Even a 1-2% drop in mortality would make a difference to egg production income.”

Since 2008, all of McDonald’s egg producers have been required to plant at least 5% tree coverage on ranges. Joy Clachan, McDonald’s UK agriculture assurance manager, said the research demonstrated that a minimum of 5% canopy cover close to the hen house is a practical way of improving hen welfare.

“We have seen how strategic tree planting can lower bird mortality rates, reduce egg seconds and help limit injurious feather pecking, so we would encourage all free-range producers to embrace the welfare and economic benefits of this farming approach,” she said.