Ž .
had its beak in water or stood in front of the drinker with raised head swallowing . The number of ‘‘active immobile’’ chicks was calculated as the sum of the birds standing or
eating or drinking.
2.2.2. Focal sampling Ž
. Since chickens lie for 80 to 90 of their time Bessei, 1992 , only behavioural
patterns expressed during the ‘‘standing’’ bouts were recorded, i.e. behaviours expressed from the moment when a bird stood up until it lay down. The observations were sampled
Ž .
during four periods of 2 days 2–3, 6–7, 13–14, 20–21 days after hatch . About 10 behavioural bouts were recorded per pen and per day of observation. Behaviours were
Ž .
recorded using the Observer 3.0 Noldus Information Technology, Netherlands . This Ž
software records duration of the different states walking, running, standing, eating, .
Ž drinking, preening and exploring litter and occurrence of the different events each step
. and interaction with a congener . A bird was considered to be walking only when it was
mobile ; when it was walking step by step, short periods of immobility were recorded as standing. Eating and drinking were considered to have stopped as soon as the bird stood
inactive, even if it was in front of a feeder or a drinker. Exploring litter included pecking and scratching the floor. Preening contained feather licking and scratching itself. The
Ž .
term interaction was used for behaviours antagonistic or not which involved contact between the interacting pair during the standing bouts: pecking, leaping, sparring,
preening each other and stepping on another bird. For analysis, standing bouts were sorted into two types: feeding bouts in which
Ž .
chicks drank or ate and other bouts non-feeding bouts . These two types of bout were analysed separately because the motivation for activities in each kind of bout was
believed to be different.
2.3. Data analysis For all data analysed, the pen was the experimental unit. Pen means were therefore
used to examine the effects of age and genetic strain. Because data were not normally distributed, they were analysed with nonparametric statistical tests using Statview 4.05.
Genetic effects were tested with the Mann–Whitney U test, and age effects for each strain using the Friedman test. Feeding and non-feeding bouts were compared using
Wilcoxon test. The correlation coefficients between body weight and the different behaviours at different ages were computed using Spearman’s rank correlation. For focal
sampling, we chose to eliminate from analysis the birds which were lame at day 17 Ž
. Ž
n s 5 in order to avoid any possible effect on general activity Weeks and Kestin, .
1997 .
3. Results
3.1. Bird growth Ž
. Body weight was significantly lower at hatching in B chicks 36.3 0.3 g than in L
Ž . Ž
. chicks 42.6 0.5 g
Z s 6.33, P - 0.001 , while it was higher at 22 days of age
Ž .
Z s 6.65, P - 0.001 : 707.3 16.2 g in B chicks versus 413.7 6.7 g in L chicks. Body weight at hatching was significantly related to 3-week body weight in B birds
Ž .
R s 0.595, n s 30, P - 0.01 , but not in L birds. Mortality rate was zero in both groups.
3.2. Leg problems No L birds became lame. Four B chicks were identified as lame at 17 days of age and
had abnormal tarsal angulation at day 22. One B chicken was lame at day 17 but did not present any tarsal defect at day 22. Another B chicken had a valgus angulation at day 22
but was not identified as being lame at day 17.
3.3. Time budget The behaviour data converted to proportions of time spent in each activity are
Ž . Ž
. presented as means and standard errors SE
Fig. 1 . Most of the birds were lying during observations. When all groups and ages were mixed, chicks spent 67 of the
Ž .
time lying, 28 of the time active immobile eating q drinking q standing and only 5 of the time walking.
Walking time did not significantly differ according to age or to genetic factor but every other behavioural pattern was significantly affected by age: in the B group, level
Ž of activity fluctuated with age numbers of birds lying, drinking, eating and standing,
respectively, H s 8.6, H s 8.34, H s 7.8, H s 7.6, df s 3, P - 0.05 using Friedman .
Ž test and activity of L chicks increased gradually with time numbers of eating and
. standing birds, respectively H s 8.49, H s 9.81, df s 3, P - 0.05, using Friedman test .
Ž .
Fig. 1. Time budget in both genetic types at different ages six repetitions of five birds per treatment .
U UU
Ž .
: P - 0.05, : P - 0.01 test: U-Mann-Whitney .
B birds spent significantly less time standing and actively immobile than L birds at Ž
. Ž
. 15 and 17 days Fig. 1 . B chicks also spent more time lying at 17 days Fig. 1 .
3.4. Standing bouts During the four 2-day periods of focal sampling, 836 standing bouts were recorded.
The mean standing bout duration was 55.1 15.4 s. Feeding and non-feeding bouts differed widely in general characteristics: mean durations of feeding bouts differed
Ž significantly from those of non-feeding bouts 212.6 83.3 s versus 19.6 8.8 s,
. Z s 3.05, P - 0.001, using Wilcoxon test, Fig. 2 . Birds walked significantly more in
Ž feeding bouts than in non-feeding bouts 33.7 4.1 s versus 3.4 0.52 s, Z s 3.05,
. P - 0.001 using Wilcoxon test .
Ž .
Fig. 2. Mean total duration of the standing bouts feeding and non-feeding bouts at different ages. Number of standing bouts registered is noted into columns. Pen of birds was the statistical unit after removing the five
U
Ž .
lame birds. P - 0.05 test: U-Mann–Whitney .
3.4.1. Feeding bouts Feeding bouts represented 21 of the recorded bouts and 74 of the total time
observed. Durations of feeding bouts in B chicks were half as long of those of L chicks Ž
. at days 2–3 and at days 20–21 Fig. 2 .
Duration and occurrence of the behavioural patterns were little affected by age: only duration of eating and number of interactions decreased in L chicks at 6–7 and 13–14
Ž .
days Table 1 . Locomotor behaviour was not significantly related to age but to genetic type, except
running, which was very rare: L chicks were more active than B chicks at days 2–3 Žwalking, standing, numbers of steps, respectively, Z s 2.56, Z s 2.19, Z s 2.74, P -
. 0.05 using Mann–Whitney’s U test , although they were heavier. The same differences
Table 1 Ž .
Duration s of different states and occurrence of different events during feeding bouts recorded on focal sampling
a
Ž .
Age days 2–3
6–7 13–14
20–21 Age effect
Genetic type meanSE
meanSE meanSE
meanSE Locomotor behaÕiour
Ž . Walking s
L 44.84.4
42.47.0 35.99.7
42.28.7 ns
B 19.44.0
67.237.8 31.013.5
18.72.8 ns
U U
U U
U U
U U
U U
Type effect ns
ns
Number of steps L
34.92.5 35.56.0
30.18.6 35.08.2
ns
B 12.22.9
53.927.4 26.111.8
16.02.3 ns
U U
U U
U
Ž .
Type effect ns
ns 0.05
Ž . Running s
L 2.20.7
0.60.3 0.70.5
1.00.4 ns
B 0.70.3
1.10.1 1.10.9
0.30.2 ns
Type effect ns
ns ns
ns
Ž . Standing s
L 100.26.5
59.614.6 62.59.6
65.117.2 ns
B 48.815.1
49.317.4 46.219.8
30.05.7 ns
U U
U U
U
Ž .
Ž .
Type effect ns
0.11 0.06
Feeding behaÕiour Ž .
Drinking s L
7.22.9 10.53.6
11.82.3 13.13.6
ns
B 9.73.8
7.53.9 13.25.7
13.54.1 ns
Type effect ns
ns ns
ns
Ž . Ž
. Eating s
L 180.142.8
116.621.0 44.06.1
104.534.2 0.05
B 70.023.1
158.744.3 78.746.8
46.211.6 ns
U U
U U
U
Type effect ns
ns ns
Other behaÕiours Ž .
Preening s L
9.42.9 3.51.0
8.34.3 8.32.7
ns
B 5.92.9
4.12.4 2.00.7
3.51.1 ns
Type effect ns
ns ns
ns
Ž . Exploring litter s
L 16.83.5
28.79.8 30.812.6
24.610.5 ns
B 6.11.8
9.02.6 6.52.9
2.00.7 ns
U U
U U
U U
U U
U U
U U
U U
U
Ž .
Type effect 0.10
U U
U U
UU U
U U
U
Number of L
5.30.8 3.51.5
1.70.5 4.71.0
interactions B
1.60.6 3.21.3
2.41.5 0.60.2
ns
U U
U U
U U
U U
U UU
U U
U U
with congener Type effect
ns ns
a
Ž .
For number of feeding bouts, see Fig. 2a. Only the non-lame birds were taken into account ns 55 .
were again significant at 3 weeks of age when B birds were twice as heavy as L birds. Eating duration was greater for L than B birds as early as 2–3 days of age. Preening did
not differ between stocks. There were more interactions between L birds than between B birds at 2–3 and 20–21 days of age. L chicks spent more time exploring litter than B
Ž .
birds at least three times longer, Z s 2.88, P - 0.01, using Mann–Whitney’s U test . 3.4.2. Non-feeding bouts
Ž .
Ž .
Duration Fig. 2b and composition of the non-feeding bouts data not shown were not affected by age or by genetic type. Only preening duration at 13–14 days of age
Ž differed between the two crossbreeds L: 3.9 0.7 s, B: 0.8 0.2 s, Z s 2.40, P - 0.05
. using Mann–Whitney’s U test .
3.4.3. Correlations between actiÕities Only L activity during feeding bouts was related to body weight: at 3 weeks of age, L
Ž chicks were less active while they were heavier
walking: R s y0.505, n s 22, .
P - 0.05; standing: R s y0.388, n s 22, P s 0.07 . Time spent standing at days 2–3 Ž
was negatively related to body weight at day 22 in L birds R s y0.639, n s 15,
. P - 0.05 .
During non-feeding bouts, there was a negative correlation between body weight at Ž
hatching and duration of walking at 3 weeks of age L: R s y0.486, P - 0.05; B: .
R s y0.459, P - 0.05, n s 30 . The more active B birds at days 2–3 were the same at Ž
20–21 days of age bout total duration: R s 0.412, P - 0.05, n s 27 ; standing:
. R s 0.409, P - 0.05, n s 27 .
4. Discussion
