ABSTRACT Egg laying strains of chickens have a strong
motivation to perch. Providing caged chickens with
perches allows them to perform their natural perching
behavior and also improves their musculoskeletal health
due to exercise. Little is known about the effect of perch
access for hens on physiological measures of stress. Our
hypothesis was that denying chickens access to perches
would elicit a stress response. The objective of this
study was to determine the effect of perch access during
all or part of life cycle on physiological homeostasis in
caged 71-wk-old White Leghorn hens. A total of 1,064
chicks were assigned randomly to cages with and without
perches (n = 14 pullet cages/perch treatment) on
day of hatch. As pullets aged, chicks were removed from
cages to provide more space. At 17 wk of age, 324 chickens
in total were assigned to laying cages consisting of 4
treatments with 9 replicates per treatment. Treatment
1 chickens never had access to perches during their
life cycle. Treatment 2 chickens had access to perches
only from 17 to 71 wk of age (laying phase). Treatment
3 chickens had access to perches only from hatch
to 16.9 wk of age (pullet phase). Treatment 4 chickens
always had access to perches during their life cycle. At
71 wk of age, chickens were sampled for measurement
of plasma catecholamines (epinephrine, norepinephrine,
and dopamine) and corticosterone; blood serotonin and
Trp; fluctuating asymmetry of shank length and width;
and adrenal weight. Only shank width differed among
treatments. Chickens with previous exposure to perches
during the pullet phase had wider shanks than chickens
without access to perches (P = 0.006), suggesting that
early perching promoted skeletal development. These
results suggest that a stress response was not elicited in
71-wk-old White Leghorn hens that always had access
to perches compared with hens that never had access to
perches during all or part of their life cycle.