Brief communication: Behavioural differences between red jungle fowl (Gallus gallus) and White Leghorn (Gallus gallus domesticus).
Captive environment may lead to unintentional changes in an animal’s genotype1 that alter
thresholds for performing behaviours essential for survival in the wild2. From an ex situ
breeding aspect, release animals should have a behavioural repertoire as close as possible to
that of their wild conspecifics. Therefore, it is of great importance that animals are as little
affected as possible by their captivity. However, it is not possible to completely avoid
changes, and according to Gilligan and Frankham3, wild animals are likely to adapt to captive
environment rapidly through unintentional natural selection. From this aspect, I have
investigated the differences between two captive populations of red jungle fowl (Gallus gallus)
(RJF) and one of White Leghorn layers (Gallus gallus domesticus) (WL), focusing on social
behaviours. The red jungle fowl originated from two populations, one from Copenhagen zoo
(COP) and one from Götala research station (GOT). They have been in captivity for different
length of time and kept under different environmental conditions. The animals used in present
study were the second generation GOT and COP and the first generation WL hatched and
reared under identical conditions at Götala research station, in order to eliminate
A group observation test focusing on social behaviours was carried out. Significant
differences were found in social distance between GOT and COP at the ages 14 weeks
(P=0.001), 18 weeks (P=0.000) and 22 weeks (P<0.001), but non between WL and any of the
others. The differences found were mainly due to different behaviours performed, such as
different foraging strategies, dust-bathing behaviours and other social interactions. This also
resulted in differences in position in the pen, with GOT spending more time on perches above
ground than COP and WL. A difference in foraging behaviours where COP had a more costly
foraging strategy than WL were seen but not documented. This is in agreement with previous
findings4 of wild-type fowl having a more costly foraging strategy than domestic fowl and
could explain the results in this study.
Even though no significant differences were found in any of the behaviours, there were some
indications of differences. According to Rushen5, chickens establish their dominance
formation during the age of 6 to 10 weeks. Since COP had a peak of aggressive behaviours
at 6 weeks old, but none of the others did, this may indicate a difference in dominance
formation between the populations, or a difference in aggressiveness in the populations. Such
differences may have effects on social structures of the animals. Modifications of social
structures may affect a species survival after being released. A difference in reaching sexual
maturation in females was also found, were the domesticated WL reached sexual maturation
at 16 weeks, followed by COP at 19 and GOT at 21 weeks. An earlier sexual maturation could
be an advantage in captivity, but it could also affect survivorship in the wild. In a number of
species, a reduced fitness has been found in captive animals that have been released back
into the wild 3.
Since no significant differences in social behaviours were found between any of the
populations, a genetic difference cannot be confirmed. These findings are in agreement with
findings in the first generation of RJF6, but do not agree with findings in the original
populations at Copenhagen zoo and Götala research center 6,7 . In the original populations,
there was a difference in social behaviours, which suggests that the environment affects the
performances of social behaviours. If this is the case, it stresses the importance of keeping
ex situ animals in an environment that as much as possible resemble the natural habitat of
the species in order to minimize unintentional changes affecting fitness in the animals.
Master student at Linköping University,Sweden
1. Price EO & King JA (1968) pp 34-45 in: Hafez ESE (eds) Adaptation of domestic animals. Lea and Febiger , Pennsylvania .
2. Kleiman DG (1989) BioScience 39, 152-161.
3. Gilligan DM, Frankham R (2003) Conservation Genetics 4, 189-197.
4. Schütz KE & Jensen P (2001) Ethology 107, 753-765.
5. Rushen J (1983) Applied Animal Behaviour 11, 55-66.
6. Håkansson J, Bratt C & Jensen P (2005) In press
7. Håkansson J & Jensen P (2005 Biological conservation 122, 431-439.
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Last updated: 06/07/06