Behavioural Elsevier
Processes,
OPEN-FIELD
IO (1985) 333-340
BEHAVIOUR
IN CHICKENS:
S. D. SUAREZ and G. G. GALLUP, Department
of Psychology,
New York
333
A REPLICATION
REVISITED
JR.
State University
of New York at Albany,
Albany,
12222 U.S.A.
(Accepted
20 January
1984)
ABSTRACT Suarez, S. D. and Gallup, G. G., Jr., 1985. Open-field behaviour A replication revisited. Behav. Processes 10: 333-340.
in chickens:
In an attempt to show that the open field can still be used as a valid measure of fear, Jones (1983) has reported a failure to replicate some of our findings. The present studies show that this was due to procedural and methodological differences. For instance, we found that birds tested in a novel environment behaved quite differently from those, as in Jones' case, which were placed in one resembling the home cage. Moreover, birds housed in isolation for two days prior to testing reacted differently than those, as again in Jones' case, which were reared in isolation from hatching to the time of testing. The results were interpreted as being consistent with our view that open-field behaviour reflects a conflict between the need to reinstate contact with conspecifics on the one hand, and evade predation on the other.
INTRODUCTION We have developed chickens,
ducks,
Suarez and Gallup, typically,
a model
rats, mice,
of open-field
1980, 1981a,
but unintentionally,
with a human as a consequence
1982a). exposed
that most animals
are subjected
imprinted
conspecifics
tested
in isolation.
or compromise
between
evade further
predatory
chickens
behaviour
tendencies
studies,
we reasoned
the implications
avian species
separated
from the mother
or broodmates
accentuate
the motivation
to reinstate
calling
encounter
during
removal
also assumes
from familiar
from a group cage and is viewed
to reinstate
as an interaction
social contact
that separation
calls for the sake of convention)
young of many precocial
0376-6357/85/$03.30
The model
are
and
activity.
could be used to assess
hood of distress
predatory
social separation
to
1980;
that animals
and restrained
they are removed
open-field
the opposing
Based upon naturalistic to here as 'distress'
to a simulated
to sudden
Therefore,
and Suarez,
The model assumes
in the open field.
because
shown applicable
(see Gallup
of being captured
from the home cage and placement
and/or
behaviour
and guinea pigs
and ambulating
and ambulation
of this model.
emit distress
calls
(referred in
Since the
calls and move about when
in the wild, procedures social contact
designed
should enhance
upon initial placement
0 1985 ElsevierSciencePublishersB.V. (Biomedical
to
the likeli-
in an open field
Division)
334
and vice versa.
When faced with
young precocial enhance
birds typically
the predatory
the initial
occurrence
still appears behaviour.
major procedural
under natural
conditions
Thus, procedures
situation
calls and ambulation
which
should minimize
(see Suarez and Gallup,
details).
being unable
ings (Gallup and Suarez,
open-field
of the open-field
of distress
(1983) reported
construct
freeze and are silent.
overtones
1981b, 1982b, 1983 for further Jones
the threat of predation
to replicate
1980) and, consequently, to be the most fruitful
The present
discrepancies
experiments
between
some of our original
find-
that a fear or emotionality framework
for interpreting
were performed
to address
the
his work and ours, and to determine
if our results were replicable.
EXPERIMENT
1
We found that chicks distress Suarez,
calling 1980).
tested in an open field in pairs take longer
and ambulating
than chicks
This was interpreted
social reinstatement
evasion
initial
the predominant
(as defined
by a novel environment
testing apparatus cage.
Because
environment, testing
response
However,
that is larger
is designed
the first experiment
chicks individually
in pair-tested
predator
chicks.
Jones
was conducted
(1983)
in an open field
than the home cage).
was, instead, to account
of another
making
he did not test animals
that Jones employed
our model
motivation,
to begin
(Gallup and
to mean that the presence
animal serves to reduce
failed to find this effect.
tested individually
very similar
for behaviour to compare
or in pairs in a familiar
The
to the home
in a novel
the effects
of
vs. an unfamiliar
environment. Material
and Methods
The subjects obtained
were 80 straight-run
from a commercial
supplier
groups in three thermostatically a 10-h photoperiod rack was shielded exposure
controlled
with continuous
access
by an opaque barrier
Half of the chicks were tested
lid.
food or water
lip marker
present.
in the center
Under both testing
circuit
brooders
in
(Sears) under The brooder
to chick chow and water.
the floor into a grid of 25 squares
identical
felt
(Gallus --____ gallus)
They were housed
in order to limit the amount of incidenta
in a plywood
(91.4 x 61.0 x 27.9 cm high)
pan.
commercial
The box was painted
covered by a clear Plexiglas
without
Red chickens
to human caretakers.
88.9 x 88.9 x 40.6 cm high. dividing
Production
at one day of age.
television
open-field
box that measured
flat black with white
lines
(each 17.5 x 17.5 cm) and was
The remaining
chicks were tested in a brooder
to the ones they were reared in but
A 17.5 x 17.5 cm square was drawn with a black of the brooder
conditions
behaviour
system that consisted
on the newspaper was monitored
of a Panasonic
lining
remotely
TV camera
the drop on a closed-
(WV-341P) and
335
microphone, recorder
a Panasonic
monitor
Testing
in a separate
ture.
Half of the chicks were
the open field. the brooder
termined
testing
Video Corp.
the experimenter
and half were tested in
chicks were
conditions
tested
apparatus.
individually
set was assigned For testing
system
as the latency in pairs,
room.
Latencies
except
that each pair was treated were
during
Sub-
of 40 min.
that time, 2400
from the group brooder
box, and both placed the apparatus
call and ambulate
in pairs,
in the center of the
lid the experimenter
left the
were scored as described
as a single unit of measurement.
were removed
sode, and the floor was wiped
and
of placement.
for a maximum
had not occurred
timed when either member
Defecations
apparatus
calling
score.
in a cardboard
to distress
in the cen-
timed on stopwatches
from the moment
chicks were removed
After lowering
apparatus.
selected
order was de-
the lid on the apparatus,
to begin distress
in the testing
and/or ambulating
together
in
from the group brooder,
square with both feet were
television
to remain
calling
Running
box, and placed
After closing
Latencies
left the room.
jects were allowed
in pairs.
each chick was removed
out of the center
via the closed-circuit
latencies
and tempera-
room alone in a cardboard
tral square of the testing
ambulated.
room illumination
block.
testing,
to the testing
transported
of the photo-
in the brooder
selected
the two testing
For individual
If distress
tested
the mid-portion
and 8 in the open field, and 16 chicks each were randomly
by randomized
ambulating
room under normal
Eight randomly
and tested under
testing
and an International
took place at 17 days of age during
period
carried
(TR-195V),
(IVC-700).
of a pair first distress
from the apparatus
above,
That is, called and/or
after each testing
clean with a damp sponge s,aked
epi-
in disiniectant.
Results The data for distress ambulation
latency
was significant
for both latency
.OOl) and ambulate apparatus
first distress
calling
with chicks
latencies
of variance
(E = 10.23; df = 3,28; p < The main effect of testing
tested in the open field taking longer
in the home cage.
with chicks
tested
for both distress
call
tested
individually.
(2 = 7.88.
in pairs taking longer
to
(F _ = 6.81;
The interaction
was sig-
(F _ = 6.81; -df = 1,28; _p i .025) and ambulation
(F - = 6.14; -df = 1,28; _p < .025).
to
The main effect of test-
(F _ = 11.75; -df = 1,28; p < .005) and ambulate
df = 1,28; p < .025) than chicks nificant
call
1, and those for
2 x 2 analysis
(F _ = 12.13; df = 1,28; _p < .005) and ambulating
was also significant, call
in Figure
An overall
to distress
df = 1,28; 2 < .Ol) than those tested ing condition
are depicted
(F = 6.87; df = 3,28; p _ < .005).
was significant,
begin distress
call latency
are shown in Figure 2.
336
Single Pairs
cl
Home Cage
Open Field
Testing Environment
Fig. 1. Mean distress call latencies by chicks tested pairs in either an open field or the home cage.
1
individually
or in
llllm q
Smgle PalrS
II
.I v
Home Cage
Open Field
Testmg Environment Fig.
2.
&an
ambulation
in either an open field Subsequent
planned
latencies by chicks the home cage.
comparisons
showed that chicks
in pairs took longer to begin distress and ambulating ever,
there were no significant
for singles
chicks
calling
tested in the open field
(F df = 1.28; -p < .OOl) _ = 18.23; -
deviations
differences
in either distress
tested singly or in pairs
for distress
and 47.8 for pairs;
for singles and 14.7 for pairs.
call latencies
HOW-
call or ambula-
in the home cage.
in the open field were 8.7
for those tested in the home cage they were 4.4 Standard
in the open field were 52.1 for singles brooder
or in pairs
(F - = 12.93; -df = 1,28; _p c .005) than those tested singly.
tion latency between Standard
tested individually
or
they were 31.4 for singles
deviations
for ambulation
and 1110.4 for pairs, while
and 81.8 for pairs.
latencies in the
331
EXPERIMENT
2
As another isolation
means
of testing
for two days prior
open field with chicks our prediction
isolate-housed
tress call and ambulate Suarez,
subjects
in groups.
in an
Consistent
the motivation
with
to reunite with
were found to take longer
than their group-housed
(1983) isolated
However,
before being ducted
should reduce
in social
their behaviour
counterparts
to first dis-
(Gallup and
1980).
Jones age.
and compared
that had been maintained
that isolation
conspecifics,
our model, we placed young chickens
to testing
chicks upon hatching
in our study subjects
isolated
to examine
and tested them at 1% weeks of
were reared
in social groups for 3 weeks
for 2 days and then tested.
the effects
obtained
The present
with chicks
study was con-
that were isolated
shortly
after hatching. Materials
and Methods
Subjects mercial
were 16 straight-run
supplier
in isolation. brooders
that were divided
group reared study.
(Welp) at one day of age.
This consisted
but not visual
or tactile,
in a brooder
The brooders
Experiment
Production
Red chickens Upon arrival,
of maintaining
to each other.
along with
8 chicks were placed in
Chicks had auditory,
Eight other chicks were
4 other same-aged
and the conditions
from a com-
chicks one per compartment
in half by metal partitions. access
obtained
of maintenance
chicks not used in this were
the same as in
1.
At 12 days of age each subject was tested individually for latencies
to distress
same as in Experiment chair facing
call and ambulate.
1, except
The testing procedures
that an experimenter
the open field for the duration
in the open field
remained
were the
seated on a
of the test.
Results The results
are shown in Figure
was no significant for either distress
difference call
Analyses
3.
between
of variance
chicks reared
showed that there
in isolation
(F - < 1; -df = 1,14) or ambulation
or in groups
(F _ < 1; -df = 1,14)
latency. The standard in isolation ambulation reared
deviation
for distress
and 20.4 for those reared
call latency was 61.1 for those reared in groups.
latency was 223.1 for those reared
in groups.
The standard
in isolation
deviation
for
and 174.5 for those
338
Fig. 3. Mean latencies to distress isolation or in groups. EXPERIMENT
the second experiment experiment
by chicks reared
in
3
Because no effects
determine
call and ambulate
utilized
of isolation
on open-field
behaviour
using chicks that were housed
our original
procedures
were found in
individually,
(Gallup and Suarez,
if group reared birds would be affected
the present 1980) to
by two days of social iso-
lation prior to testing. Materials
and Methods
Subjects were 20 straight-run preceding
experiments.
tained as previously
described.
isolatio,l as in Experiment handling
Production
They were housed
and were placed
2.
Red chickens
obtained
in a group upon arrival
as in the
and main-
At 22 days of age, 10 chicks were placed 'The remaining
10 subjects
in a group in a brooder
received
in
equivalent
with 3 other same-aged
chicks not used in this study. At 24 days of age, each chick was given an open-field latencies
to begin distress
as in Experiment
2.
calling
and ambulating
All tests were conducted
test and timed for
out of the center
in the absence
square
of an experimenter.
Results The data are shown in Figure for heterogeneity
of variance
which had been housed cantly longer
4.
Analyses
of variance
by a loglo transformation
in isolation
to first distress
of scores corrected
indicated
for two days prior to testing
that chicks took signifi-
call (F _ = 6.10; -df = 1,lS; _p < .025) and
(F - = 9.72; -df = 1,18; _p < .Ol) than those housed in groups. The standard deviations of transformed scores for distress call latency were
ambulate
.73 for isolate housed the standard
deviations
and .41 for group housed were
chicks;
.55 for isolate housed
for ambulation
latency
and .40 for group housed
339
subjects.
Fig. 4. Mean latencies to distress call and ambulate by chicks reared in groups and housed either in isolation or in groups for two days prior to testing. DISCUSSION Although sooner
Jones
failure
to replicate
ing environment
It is important
Jones
with predictions
those raised
derived
If chicks were raised were
to reiterate,
explanation
in isolation
soon after hatching
the home cage may trigger motivation
In support
of this hypothesis,
of age, no
call or ambulate.
For such chicks,
latencies
calling
chicks
in Experiment
the period when early imprinting
two days prior to testing,
begin distress
our findings.
How-
are likely to imprint upon
to that of group-reared
in similar
in the
2 and 3 pro-
to duplicate
removal
to reunite with the home cage.
may be similar
than
chicks
from
The dynamseparated
to begin distress
calling
in an open field.
in a group throughout isolated
is
that chicks
and ambulating
of Experiments
to either distress
of their home environment.
thus resulting
effect which
or groups and tested at 1% weeks
the static
ics of this motivation
that when birds are
our findings
calling
for his inability
in isolation
and ambulating
however,
effect does,
the fact that Jones tested his subjects
found in latencies
features
a clue as to his
in their normal hous-
the pair-testing
to replicate
to begin distress
Besides
move
from our model.
ever, chicks placed
from conspecifics,
1 provides
than in an open field, the results
vide a further possible
differences
situation,
a failure
take longer
in a group.
home cage rather
Experiment
there is a robust pair-testing
(1983) also reported
in isolation
tested in pairs actually
When chicks are tested
than in a novel
in a novel environment
consistent
housed
that chicks
our results.
rather
indeed, not occur. tested
(1983) claims
than those tested individually,
showed significantly
and ambulating
than chicks
3 which were maintained typically
takes place and
longer latencies
that remained
housed
to
in groups
340
In this instance
the effect of isolation
tion of social reinstatement
would be to provide
tendencies,
for the habitua-
and thus the effects
are again con-
sistent with our model. We do not measure
latency
to first audible
latency
to emit the first high intensity,
appears
to confuse
or equate distress
tions. These two vocalizations different. bility".
He also argues
However,
because
minor postural
are both structurally
are never completely
adjustments.
terms of some objective, of some circumscribed
of respiratory
Therefore,
quite
by "complete
in reality motionless
movements,
criterion
immo-
the animal would (even when eye movements,
freezing must be operationalized
easily discernible
the (1983)
peep vocaliza-
and functionally
is characterized
for such a state to be obtained
of the occurrence
but rather call. Jones
calls with low intensity
that freezing
have to be dead. Live animals asleep)
vocalization,
shrill distress
like latency
and
in
to move out
area of an open field.
REFERENCES Gallup, G.G., Jr. and Suarez, S.D., 1980. An ethological analysis of open-field behaviour in chickens. Anim.Behav., 28: 368-378. Jones, R.B., 1983. Fear responses in domestic chicks as a function of the social environment. Behav. Proc., 8: 309-326. Suarez, S.D. and Gallup, G.G., Jr., 1980. An ethological analysis of open-field behaviour in ducks Anas platyrhynchos. Bird Behav., 2 : 93-105. Suarez, S.D. and Gallup, G.G., Jr., 1981a. An ethological analysis of open-field behaviour in rats and mice. Learn. Motiv., 12: 342-363. Suarez, S.D. and Gallup, G.G., Jr., 1981b. Predatory overtones of open-field testing in chickens. Anim. Learn. Behav., 9: 153-163. Suarez, S.D. and Gallup, G.G., Jr., 1982a. Open-field behaviour in guinea pigs: Developmental and adaptive considerations. Behav. Proc., 7: 267-274. Suarez, S.D. and Gallup, G.G., Jr., 1982b. Open-field behavior in chickens: The experimenter is a predator. J. Comp. Physiol. Psychol., 96: 432-439. Suarez, S.D. and Gallup, G.G., Jr., 1983. Social reinstatement and open-field testing in chickens. Anim. Learn. Behav., 11: 119-126.
Reprint requests should be sent to G.G. Gallup, chology, SUNY-Albany, Albany, NY, 12222, U.S.A.
Jr., Department
of Psy-