Domestication effects on foraging strategy, social behaviour and different fear responses: a comparison between the red junglefowl (Gallus gallus) and a modern layer strain

Leghorns conserve their energy for feeding

source: Karin E. Schutz, Bjorn Forkman and Per Jensen
Applied Animal Behaviour Science vol 74 no 1, 2001
starts p 1, 14 pages long

Animals can change in appearance and behaviour as a result of domestication, because their lives are easier, and humans may select for certain traits. Selecting for a particular trait may also affect other traits. Resource allocation theory argues that animals geared for high production (putting on weight, or producing offspring) will spend less time on non-feeding activities. Red junglefowl are found in the wild, and domestic fowl appear to have descended from them, so they can be used as an example of ‘wild’ fowl in research on domestication. Junglefowl from a Swedish zoo were compared with White Leghorn layers in this study. The Leghorns have been bred as layers and to convert food efficiently. The birds were reared under the same conditions, and tested as pairs, since they were calmer than when tested alone.

The White Leghorns were found to conserve energy in different tests. They preferred familiar food, while the junglefowl preferred novel food, though that meant taking longer to eat the same amount. The Leghorns were generally less active, and responded less to frightening stimuli. Some animals, including domestic fowls, have been found to prefer looking for food rather than eating food that is easily available. This may be because looking for food can give animals information about where food can be found. Broilers tend to forage less and be generally less active than layers, according to some studies, and it has also been found that high efficiency of food conversion is linked to lower levels of aggression and activity.

Aggressive behaviour and social activity may be less necessary for domestic animals, since they do not need to compete for food as much as wild animals. However, high ranking domestic chickens can still gain advantages like better roosts. Male Leghorns in this study crowed more when seeking food, displayed more to females, and were more aggressive with humans, when being handled, compared with junglefowl. This male Leghorn aggression could be linked to layers being selected in terms of reproductive success. Junglefowl, however, were generally more vocal in the study, which could mean that their social motivation was higher than that of the Leghorns.

The Leghorns reacted less to a model of a hawk above them, than did the junglefowls. This lower level of reactivity to predators has been found in other domestic species compared with wild counterparts, such as ducks and trout.