Slow-Growing Broilers Show Positive Welfare Behaviors

The Problem

Conventional broiler chickens are bred to grow rapidly, reaching market weight in six to eight weeks. Demand for slow-growing broilers, which take up to 12 weeks to mature, is growing in some international markets. Limited research has directly compared how growth rate, genetics and management factors influence broiler behavior, an important indicator of animal welfare.

The Work

Rosie Whittle, a poultry science postdoctoral fellow with the Center for Food Animal Wellbeing, and Shawna Weimer, Assistant Professor of Poultry Science and director of the center, conducted a study with colleagues at Purdue University examining the effects of genetic strain, stocking density and age on broiler behavior. The researchers analyzed video recordings of conventional and slow-growing broilers at designated time points to document behaviors such as standing, walking, preening and sitting posture. The behaviors were evaluated relative to both age and physiological development to better understand how growth rate influences welfare-related activity.

The Results

The study showed clear behavioral differences between slow-growing broilers and conventional broilers which were bred to grow faster. A greater proportion of slow-growing broilers were observed standing, walking and preening — behaviors associated with positive welfare — while conventional broilers more frequently displayed a lateral sitting posture. Stocking density had little effect on behavior, indicating that genetic strain and growth rate were more influential factors.

The Value

While slow-growing broilers have not seen the same market expansion in the United States as they have in some European markets, the results of the study enhance the understanding of the effects of growth rate on broiler behavior. Weimer pointed out that “animal welfare is quite dynamic” and emphasized that further investigations of broiler behavior should be undertaken. Whittle also stressed that their research was focused on understanding the effects of growth rate on broiler behavior, not necessarily what is best for companies or consumers. The researchers noted that future research should expand to consider different genotypes of broilers to avoid generalizing based on the genotypes used in this study.