Epsilon Archive for Student Projects

Abstract

Broiler breeders are essential for broiler meat production, yet little is known about their behavior.
Animals in production systems are often housed in barren environments that fail to meet their
behavioral needs, potentially impairing welfare. Environmental enrichment, when biologically
relevant and practically feasible, may improve adaptability and well-being for poultry in
production. This study investigated whether a more varied and complex rearing environment—
including multiple perch types and additional litter substrates, affected the behavior and growth of
broiler breeder pullets (Ross 308) on a commercial farm in Sweden. The study used pullets from a
total of 16 pens, with 8 pens assigned to each treatment. There were approximately 2,250 hens in
each pen and 18,000 hens in each treatment. Behavioral assessments were conducted using a novel
object/open field test, focusing on activity, exploring behaviors, affective state-behaviors, distinct
stress-related behaviors, and potential play behaviors. Three hens were randomly selected from
each treatment. The enriched group showed significantly more foraging behavior (χ² = 5.026, p =
0.02) and increased activity towards a trend in latency to first step (χ² = 3.103, p = 0.078)
compared to the control group. No differences were found in stress-related or micro-behaviors,
and play behaviors were not observed. Differences in growth were investigated through body
weight and variation in body weight within pens in four time periods (period 1 (1-5w), period 2 (6-
10w), period 3 (11-15w) and period 4 (16-20w) where 70 hens were randomly selected and
weighed once or twice a week throughout the entire rearing period. While body weight did not
differ between groups, the enriched group had significantly lower weight variation within pens in
period 3 (F = 9.49, p = 0.008) and a trend in period 4 (F=3,905, p=0,069), with values aligning
with industry standards. These findings suggest that environmental complexity may improve
behavioral adaptability and uniformity in broiler breeder pullets.