Woody breast, sometimes called wooden breast, has become a familiar and costly problem for today’s broiler industry, Cirenio Hisasaga, doctoral student at the University of California, Davis, explained at the 2025 Poultry Science Association annual meeting.
Woody breast affects chicken breast muscles. Although processors and producers have dealt with its economic impacts for years, new research is examining wing-span partitioning to identify the disease in live birds, aiming to improve welfare and reduce industry costs.
Why woody breast matters
Woody breast is costly for the industry and leads to consumer dissatisfaction.
“As a consumer, if you were to purchase a severely affected breast, you would find it to be very hard, and some even characterize it as a crunchy eating experience,” Hisasaga said.
Economically, the issue is substantial. With breast meat downgraded and consumers unsatisfied, woody breast is estimated to cost the poultry industry around $200 million annually. Woody breast is also an animal-welfare concern.
The big question that hasn’t been answered, Hisasaga pointed out, is how woody breast affects the bird itself.
Previous findings
Earlier research suggested that woody breast may limit birds’ physical performance. A 2016 study by Kawasaki et al. found differences in movement and posture between birds with woody breast and those with normal breast.
Birds with woody breast showed a forward-leaning position and downward posture, and had difficulty fully extending their wings. However, that study included only 30 birds.
A follow-up study by Shea et al., in 2023, focused on birds found on their backs in commercial houses. Researchers suggested that the limited wingspan of birds with woody breast prevents them from righting themselves. During the study, 19 of 20 birds found on their backs had limited wingspan, but only nine showed signs of woody breast. The study results didn’t clearly show whether woody breast alone was responsible.
Hisasaga’s research is shedding light on what woody breast may mean for the bird itself and how producers might identify severe cases before birds reach the processing plant.
Current study
Hisasaga wanted to answer two key questions with his study:
- Can wing separation be used as a live indicator of woody breast in broilers?
- Does severe wing separation affect a bird’s ability to right itself?
“Our study aimed to determine whether wing partition can indicate woody breast severity in market-age broilers and to determine its impact on the ability to right. If woody breast is associated with wing partition, we hypothesize that we can use wing partition as a live indicator of woody breast,” Hisasaga said.
His study evaluated 59 market-age broilers, 45 to 52 days of age, from three commercial farms. Birds were grouped based on wing position when wings were fully extended backward:
- No wing partition: wings touched
- Moderate wing partition: wings separated but nearly touched
- Severe wing partition: wings showed a large gap and didn’t extend beyond their body
Afterward, birds were evaluated post-mortem for woody breast using a standard three-point system: normal, moderate or severe. The results revealed that using the wing partition to identify woody breast was highly accurate. When any wing partition (moderate or severe) was used to identify woody breast, the method showed 94.9% accuracy.
Researchers then examined severe wing partition as an indicator of severe woody breast. This resulted in only a slight drop in accuracy to 89.8%. “We can utilize severe wing partition as an indicator of severe woody breast,” Hisasaga said, though he emphasized that larger studies are needed.
Implications for bird welfare
This study also examined whether wing partition affected a bird’s ability to right itself, with birds placed on their backs and given 60 seconds to stand.
Among the birds with no or moderate wing partition, 27 out of 31 were able to right themselves. In contrast, most of the birds with severe wing partition (23 out of 28) were unable to right themselves.
Time was also a factor. Normal birds were able to right themselves quickly. As the severity of woody breast increased, the birds required more time. Birds with severe woody breast had the longest median time, 60 seconds, which was the maximum allowed.
Hisasaga noted that welfare becomes a greater concern when birds are unable to right themselves. “If birds spend a long period of time on their backs, this can lead to pulmonary congestion, creating pressure from the breast on the respiratory system, and can eventually lead to death,” he explained.
Implications for producers
The key takeaway for producers is that wing partition offers a practical, noninvasive way to identify woody breast in live birds. “Wing partition can be a promising, noninvasive technique to identify woody breast,” Hisasaga said.
More research and larger sample sizes are needed, he cautioned. Hisasaga believes the study holds promise for detecting woody breast earlier, thereby improving management decisions and helping producers and researchers better understand the welfare implications without relying solely on post-mortem evaluation.
This simple look at how a bird holds its wings may offer valuable insight into one of the industry’s most challenging muscle disorders.
