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-

Open-field behaviour in chickens: A replication revisited.

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 f...
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